1 Introduction

This document defines mechanisms that are anticipated to be used with the current version of PKCS #11.

All text is normative unless otherwise labeled.

1.1 IPR Policy

This specification is provided under the RF on RAND Terms Mode of the OASIS IPR Policy, the mode chosen when the Technical Committee was established. For information on whether any patents have been disclosed that may be essential to implementing this specification, and any offers of patent licensing terms, please refer to the Intellectual Property Rights section of the TC's web page (https://www.oasis-open.org/committees/pkcs11/ipr.php).

1.2 Terminology

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in [RFC2119]

1.3 Definitions

For the purposes of this standard, the following definitions apply. Please refer to the [PKCS#11-Base] for further definitions:

AES Advanced Encryption Standard, as defined in FIPS PUB 197.

CAMELLIA The Camellia encryption algorithm, as defined in RFC 3713.

BLOWFISH The Blowfish Encryption Algorithm of Bruce Schneier, www.schneier.com.

CBC Cipher-Block Chaining mode, as defined in FIPS PUB 81.

CDMF Commercial Data Masking Facility, a block encipherment method specified by International Business Machines Corporation and based on DES.

CMAC Cipher-based Message Authenticate Code as defined in [NIST sp800-38b] and [RFC 4493].

CMS Cryptographic Message Syntax (see RFC 2630)

CT-KIP Cryptographic Token Key Initialization Protocol (as defined in [CT-KIP])

DES Data Encryption Standard, as defined in FIPS PUB 46-3.

DSA Digital Signature Algorithm, as defined in FIPS PUB 186-2.

EC Elliptic Curve

ECB Electronic Codebook mode, as defined in FIPS PUB 81.

ECDH Elliptic Curve Diffie-Hellman.

ECDSA Elliptic Curve DSA, as in ANSI X9.62.

ECMQV Elliptic Curve Menezes-Qu-Vanstone

GOST 28147-89 The encryption algorithm, as defined in Part 2 [GOST 28147-89] and [RFC 4357] [RFC 4490], and RFC [4491].

GOST R 34.11-94 Hash algorithm, as defined in [GOST R 34.11-94] and [RFC 4357], [RFC 4490], and [RFC 4491].

GOST R 34.10-2001 The digital signature algorithm, as defined in [GOST R 34.10-2001] and [RFC 4357], [RFC 4490], and [RFC 4491].

IV Initialization Vector.

MAC Message Authentication Code.

MQV Menezes-Qu-Vanstone

OAEP Optimal Asymmetric Encryption Padding for RSA.

PKCS Public-Key Cryptography Standards.

PRF Pseudo random function.

PTD Personal Trusted Device, as defined in MeT-PTD

RSA The RSA public-key cryptosystem.

SHA-1 The (revised) Secure Hash Algorithm with a 160-bit message digest, as defined in FIPS PUB 180-2.

SHA-224 The Secure Hash Algorithm with a 224-bit message digest, as defined in RFC 3874. Also defined in FIPS PUB 180-2 with Change Notice 1.

SHA-256 The Secure Hash Algorithm with a 256-bit message digest, as defined in FIPS PUB 180-2.

SHA-384 The Secure Hash Algorithm with a 384-bit message digest, as defined in FIPS PUB 180-2.

SHA-512 The Secure Hash Algorithm with a 512-bit message digest, as defined in FIPS PUB 180-2.

SSL The Secure Sockets Layer 3.0 protocol.

SO A Security Officer user.

TLS Transport Layer Security.

WIM Wireless Identification Module.

WTLS Wireless Transport Layer Security.

1.4 Normative References

[ARIA] National Security Research Institute, Korea, “Block Cipher Algorithm ARIA”,
URL: http://tools.ietf.org/html/rfc5794

[BLOWFISH] B. Schneier. Description of a New Variable-Length Key, 64-Bit Block Cipher (Blowfish), December 1993.
URL: https://www.schneier.com/paper-blowfish-fse.html

[CAMELLIA] M. Matsui, J. Nakajima, S. Moriai. A Description of the Camellia Encryption Algorithm, April 2004.
URL: http://www.ietf.org/rfc/rfc3713.txt

[CDMF] Johnson, D.B The Commercial Data Masking Facility (CDMF) data privacy algorithm, March 1994.
URL: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5389557

[CHACHA] D. Bernstein, ChaCha, a variant of Salsa20, Jan 2008.
URL: http://cr.yp.to/chacha/chacha-20080128.pdf

[DH] W. Diffie, M. Hellman. New Directions in Cryptography. Nov, 1976.
URL: http://www-ee.stanford.edu/~hellman/publications/24.pdf

[FIPS PUB 81] NIST. FIPS 81: DES Modes of Operation. December 1980.

URL: http://csrc.nist.gov/publications/fips/fips81/fips81.htm

[FIPS PUB 186-4] NIST. FIPS 186-4: Digital Signature Standard. July 2013.
URL: http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf

[FIPS PUB 197] NIST. FIPS 197: Advanced Encryption Standard. November 26, 2001.
URL: http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf

[FIPS SP 800-56A] NIST. Special Publication 800-56A Revision 2: Recommendation for Pair-Wise Key Establishment Schemes Using Discrete Logarithm Cryptography, May 2013.
URL: http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-56Ar2.pdf

[FIPS SP 800-108] NIST. Special Publication 800-108 (Revised): Recommendation for Key Derivation Using Pseudorandom Functions, October 2009.
URL: https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-108.pdf

[GOST] V. Dolmatov, A. Degtyarev. GOST R. 34.11-2012: Hash Function. August 2013.
URL: http://tools.ietf.org/html/rfc6986

[MD2] B. Kaliski. RSA Laboratories. The MD2 Message-Digest Algorithm. April, 1992.
URL: http://tools.ietf.org/html/rfc1319

[MD5] RSA Data Security. R. Rivest. The MD5 Message-Digest Algorithm. April, 1992.
URL: http://tools.ietf.org/html/rfc1319

[OAEP] M. Bellare, P. Rogaway. Optimal Asymmetric Encryption – How to Encrypt with RSA. Nov 19, 1995.
URL: http://cseweb.ucsd.edu/users/mihir/papers/oae.pdf

[PKCS11-Base] PKCS #11 Cryptographic Token Interface Base Specification Version 3.0. Edited by Chris Zimman and Dieter Bong. Latest version. https://docs.oasis-open.org/pkcs11/pkcs11-base/v3.0/pkcs11-base-v3.0.html.

[PKCS11-Hist] PKCS #11 Cryptographic Token Interface Historical Mechanisms Specification Version 3.0. Edited by Chris Zimman and Dieter Bong. Latest version. https://docs.oasis-open.org/pkcs11/pkcs11-hist/v3.0/pkcs11-hist-v3.0.html.

[PKCS11-Prof] PKCS #11 Cryptographic Token Interface Profiles Version 3.0. Edited by Tim Hudson. Latest version. https://docs.oasis-open.org/pkcs11/pkcs11-profiles/v3.0/pkcs11-profiles-v3.0.html.

[POLY1305] D.J. Bernstein. The Poly1305-AES message-authentication code. Jan 2005.
URL: https://cr.yp.to/mac/poly1305-20050329.pdf

[RFC2119] Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels”, BCP 14, RFC 2119, March 1997.
URL: http://www.ietf.org/rfc/rfc2119.txt.

[RIPEMD] H. Dobbertin, A. Bosselaers, B. Preneel. The hash function RIPEMD-160, Feb 13, 2012.
URL: http://homes.esat.kuleuven.be/~bosselae/ripemd160.html

[SALSA] D. Bernstein, ChaCha, a variant of Salsa20, Jan 2008.
URL: http://cr.yp.to/chacha/chacha-20080128.pdf

[SEED] KISA. SEED 128 Algorithm Specification. Sep 2003.
URL: http://seed.kisa.or.kr/html/egovframework/iwt/ds/ko/ref/%5B2%5D_SEED+128_Specification_english_M.pdf

[SHA-1] NIST. FIPS 180-4: Secure Hash Standard. March 2012.
URL: http://csrc.nist.gov/publications/fips/fips180-4/fips-180-4.pdf

[SHA-2] NIST. FIPS 180-4: Secure Hash Standard. March 2012.
URL: http://csrc.nist.gov/publications/fips/fips180-4/fips-180-4.pdf

[TWOFISH] B. Schneier, J. Kelsey, D. Whiting, C. Hall, N. Ferguson. Twofish: A 128-Bit Block Cipher. June 15, 1998.
URL: https://www.schneier.com/paper-twofish-paper.pdf

1.5 Non-Normative References

[CAP-1.2] Common Alerting Protocol Version 1.2. 01 July 2010. OASIS Standard.
URL: http://docs.oasis-open.org/emergency/cap/v1.2/CAP-v1.2-os.html

[AES KEYWRAP] National Institute of Standards and Technology, NIST Special Publication 800-38F, Recommendation for Block Cipher Modes of Operation: Methods for Key Wrapping, December 2012, http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-38F.pdf

[ANSI C] ANSI/ISO. American National Standard for Programming Languages – C. 1990.

[ANSI X9.31] Accredited Standards Committee X9. Digital Signatures Using Reversible Public Key Cryptography for the Financial Services Industry (rDSA). 1998.

[ANSI X9.42] Accredited Standards Committee X9. Public Key Cryptography for the Financial Services Industry: Agreement of Symmetric Keys Using Discrete Logarithm Cryptography. 2003.

[ANSI X9.62] Accredited Standards Committee X9. Public Key Cryptography for the Financial Services Industry: The Elliptic Curve Digital Signature Algorithm (ECDSA). 1998.

[ANSI X9.63] Accredited Standards Committee X9. Public Key Cryptography for the Financial Services Industry: Key Agreement and Key Transport Using Elliptic Curve Cryptography. 2001.
URL: http://webstore.ansi.org/RecordDetail.aspx?sku=X9.63-2011

[BRAINPOOL] ECC Brainpool Standard Curves and Curve Generation, v1.0, 19.10.2005
URL: http://www.ecc-brainpool.org

[CT-KIP] RSA Laboratories. Cryptographic Token Key Initialization Protocol. Version 1.0, December 2005.
URL: ftp://ftp.rsasecurity.com/pub/otps/ct-kip/ct-kip-v1-0.pdf.

[CC/PP] CCPP-STRUCT-VOCAB, G. Klyne, F. Reynolds, C. , H. Ohto, J. Hjelm, M. H. Butler, L. Tran, Editors, W3C Recommendation, 15 January 2004,
URL: http://www.w3.org/TR/2004/REC-CCPP-struct-vocab-20040115/
Latest version available at http://www.w3.org/TR/CCPP-struct-vocab/

[LEGIFRANCE] Avis relatif aux paramètres de courbes elliptiques définis par l'Etat français (Publication of elliptic curve parameters by the French state)
URL: https://www.legifrance.gouv.fr/affichTexte.do?cidTexte=JORFTEXT000024668816

[NIST AES CTS] National Institute of Standards and Technology, Addendum to NIST Special Publication 800-38A, “Recommendation for Block Cipher Modes of Operation: Three Variants of Ciphertext Stealing for CBC Mode”
URL: http://csrc.nist.gov/publications/nistpubs/800-38a/addendum-to-nist_sp800-38A.pdf

[PKCS11-UG] PKCS #11 Cryptographic Token Interface Usage Guide Version 2.41. Edited by John Leiseboer and Robert Griffin. version: http://docs.oasis-open.org/pkcs11/pkcs11-ug/v2.40/pkcs11-ug-v2.40.html.

[RFC 2865] Rigney et al, “Remote Authentication Dial In User Service (RADIUS)”, IETF RFC2865, June 2000.
URL: http://www.ietf.org/rfc/rfc2865.txt.

[RFC 3686] Housley, “Using Advanced Encryption Standard (AES) Counter Mode With IPsec Encapsulating Security Payload (ESP),” IETF RFC 3686, January 2004.
URL: http://www.ietf.org/rfc/rfc3686.txt.

[RFC 3717] Matsui, et al, ”A Description of the Camellia Encryption Algorithm,” IETF RFC 3717, April 2004.
URL: http://www.ietf.org/rfc/rfc3713.txt.

[RFC 3610] Whiting, D., Housley, R., and N. Ferguson, “Counter with CBC-MAC (CCM)", IETF RFC 3610, September 2003.
URL: http://www.ietf.org/rfc/rfc3610.txt

[RFC 3874] Smit et al, “A 224-bit One-way Hash Function: SHA-224,” IETF RFC 3874, June 2004.
URL: http://www.ietf.org/rfc/rfc3874.txt.

[RFC 3748] Aboba et al, “Extensible Authentication Protocol (EAP)”, IETF RFC 3748, June 2004.
URL: http://www.ietf.org/rfc/rfc3748.txt.

[RFC 4269] South Korean Information Security Agency (KISA) “The SEED Encryption Algorithm”, December 2005.
URL: ftp://ftp.rfc-editor.org/in-notes/rfc4269.txt

[RFC 4309] Housley, R., “Using Advanced Encryption Standard (AES) CCM Mode with IPsec Encapsulating Security Payload (ESP),” IETF RFC 4309, December 2005.
URL: http://www.ietf.org/rfc/rfc4309.txt

[RFC 4357] V. Popov, I. Kurepkin, S. Leontiev “Additional Cryptographic Algorithms for Use with GOST 28147-89, GOST R 34.10-94, GOST R 34.10-2001, and GOST R 34.11-94 Algorithms”, January 2006.
URL: http://www.ietf.org/rfc/rfc4357.txt

[RFC 4490] S. Leontiev, Ed. G. Chudov, Ed. “Using the GOST 28147-89, GOST R 34.11-94,GOST R 34.10-94, and GOST R 34.10-2001 Algorithms with Cryptographic Message Syntax (CMS)”, May 2006.
URL: http://www.ietf.org/rfc/rfc4490.txt

[RFC 4491] S. Leontiev, Ed., D. Shefanovski, Ed., “Using the GOST R 34.10-94, GOST R 34.10-2001, and GOST R 34.11-94 Algorithms with the Internet X.509 Public Key Infrastructure Certificate and CRL Profile”, May 2006.
URL: http://www.ietf.org/rfc/rfc4491.txt

[RFC 4493] J. Song et al. RFC 4493: The AES-CMAC Algorithm. June 2006.
URL: http://www.ietf.org/rfc/rfc4493.txt

[RFC 5705] Rescorla, E., “The Keying Material Exporters for Transport Layer Security (TLS)”, RFC 5705, March 2010.
URL: http://www.ietf.org/rfc/rfc5705.txt

[RFC 5869] H. Krawczyk, P. Eronen, “HMAC-based Extract-and-Expand Key Derivation Function (HKDF)“, May 2010
URL: http://www.ietf.org/rfc/rfc5869.txt

[RFC 7539] Y Nir, A. Langley. RFC 7539: ChaCha20 and Poly1305 for IETF Protocols, May 2015
URL: https://tools.ietf.org/rfc/rfc7539.txt

[RFC 7748] Aboba et al, “Elliptic Curves for Security”, IETF RFC 7748, January 2016
URL: https://tools.ietf.org/html/rfc7748

[RFC 8032] Aboba et al, “Edwards-Curve Digital Signature Algorithm (EdDSA)”, IETF RFC 8032, January 2017
URL: https://tools.ietf.org/html/rfc8032

[SEC 1] Standards for Efficient Cryptography Group (SECG). Standards for Efficient Cryptography (SEC) 1: Elliptic Curve Cryptography. Version 1.0, September 20, 2000.

[SEC 2] Standards for Efficient Cryptography Group (SECG). Standards for Efficient Cryptography (SEC) 2: Recommended Elliptic Curve Domain Parameters. Version 1.0, September 20, 2000.

[SIGNAL] The X3DH Key Agreement Protocol, Revision 1, 2016-11-04, Moxie Marlinspike, Trevor Perrin (editor)
URL: https://signal.org/docs/specifications/x3dh/

[TLS] [RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC 2246, January 1999. http://www.ietf.org/rfc/rfc2246.txt, superseded by [RFC4346] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.1", RFC 4346, April 2006. http://www.ietf.org/rfc/rfc4346.txt, which was superseded by [5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, August 2008.
URL: http://www.ietf.org/rfc/rfc5246.txt

[TLS12] [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, August 2008.
URL: http://www.ietf.org/rfc/rfc5246.txt

[TLS13] [RFC8446] E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, August 2018.
URL: http://www.ietf.org/rfc/rfc8446.txt

[WIM] WAP. Wireless Identity Module. — WAP-260-WIM-20010712-a. July 2001.
URL: http://technical.openmobilealliance.org/tech/affiliates/LicenseAgreement.asp?DocName=/wap/wap-260-wim-20010712-a.pdf

[WPKI] Wireless Application Protocol: Public Key Infrastructure Definition. — WAP-217-WPKI-20010424-a. April 2001.
URL: http://technical.openmobilealliance.org/tech/affiliates/LicenseAgreement.asp?DocName=/wap/wap-217-wpki-20010424-a.pdf

[WTLS] WAP. Wireless Transport Layer Security Version — WAP-261-WTLS-20010406-a. April 2001.
URL: http://technical.openmobilealliance.org/tech/affiliates/LicenseAgreement.asp?DocName=/wap/wap-261-wtls-20010406-a.pdf

[XEDDSA] The XEdDSA and VXEdDSA Signature Schemes - Revision 1, 2016-10-20, Trevor Perrin (editor)
URL: https://signal.org/docs/specifications/xeddsa/

[X.500] ITU-T. Information Technology — Open Systems Interconnection — The Directory: Overview of Concepts, Models and Services. February 2001. Identical to ISO/IEC 9594-1

[X.509] ITU-T. Information Technology — Open Systems Interconnection — The Directory: Public-key and Attribute Certificate Frameworks. March 2000. Identical to ISO/IEC 9594-8

[X.680] ITU-T. Information Technology — Abstract Syntax Notation One (ASN.1): Specification of Basic Notation. July 2002. Identical to ISO/IEC 8824-1

[X.690] ITU-T. Information Technology — ASN.1 Encoding Rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER), and Distinguished Encoding Rules (DER). July 2002. Identical to ISO/IEC 8825-1

2 Mechanisms

A mechanism specifies precisely how a certain cryptographic process is to be performed. PKCS #11 implementations MAY use one of more mechanisms defined in this document.

The following table shows which Cryptoki mechanisms are supported by different cryptographic operations. For any particular token, of course, a particular operation may well support only a subset of the mechanisms listed. There is also no guarantee that a token which supports one mechanism for some operations supports any other mechanism for any other operation (or even supports that same mechanism for any other operation). For example, even if a token is able to create RSA digital signatures with the CKM_RSA_PKCS mechanism, it may or may not be the case that the same token can also perform RSA encryption with CKM_RSA_PKCS.

Each mechanism description is be preceded by a table, of the following format, mapping mechanisms to API functions.

Functions

Mechanism

Encrypt

Decrypt

Sign

Verify

VR¹

Digest

Gen.

Key/

Key

Pair

Wrap

Unwrap

Derive

¹ SR = SignRecover, VR = VerifyRecover.

2 Single-part operations only.

3 Mechanism can only be used for wrapping, not unwrapping.

The remainder of this section will present in detail the mechanisms supported by Cryptoki and the parameters which are supplied to them.

In general, if a mechanism makes no mention of the ulMinKeyLen and ulMaxKeyLen fields of the CK_MECHANISM_INFO structure, then those fields have no meaning for that particular mechanism.

2.1 RSA

Table 1, Mechanisms vs. Functions

	Functions
Mechanism	Encrypt & Decrypt	Sign & Verify	SR & VR¹	Digest	Gen. Key/ Key Pair	Wrap & Unwrap	Derive
CKM_RSA_PKCS_KEY_PAIR_GEN					ü
CKM_RSA_X9_31_KEY_PAIR_GEN					ü
CKM_RSA_PKCS	ü²	ü²	ü			ü
CKM_RSA_PKCS_OAEP	ü²					ü
CKM_RSA_PKCS_PSS		ü²
CKM_RSA_9796		ü²	ü
CKM_RSA_X_509	ü²	ü²	ü			ü
CKM_RSA_X9_31		ü²
CKM_SHA1_RSA_PKCS		ü
CKM_SHA256_RSA_PKCS		ü
CKM_SHA384_RSA_PKCS		ü
CKM_SHA512_RSA_PKCS		ü
CKM_SHA1_RSA_PKCS_PSS		ü
CKM_SHA256_RSA_PKCS_PSS		ü
CKM_SHA384_RSA_PKCS_PSS		ü
CKM_SHA512_RSA_PKCS_PSS		ü
CKM_SHA1_RSA_X9_31		ü
CKM_RSA_PKCS_TPM_1_1	ü²					ü
CKM_RSA_PKCS_OAEP_TPM_1_1	ü²					ü
CKM_SHA3_224_RSA_PKCS		ü
CKM_SHA3_256_RSA_PKCS		ü
CKM_SHA3_384_RSA_PKCS		ü
CKM_SHA3_512_RSA_PKCS		ü
CKM_SHA3_224_RSA_PKCS_PSS		ü
CKM_SHA3_256_RSA_PKCS_PSS		ü
CKM_SHA3_384_RSA_PKCS_PSS		ü
CKM_SHA3_512_RSA_PKCS_PSS		ü

2.1.1 Definitions

This section defines the RSA key type “CKK_RSA” for type CK_KEY_TYPE as used in the CKA_KEY_TYPE attribute of RSA key objects.

Mechanisms:

CKM_RSA_PKCS_KEY_PAIR_GEN

CKM_RSA_PKCS

CKM_RSA_9796

CKM_RSA_X_509

CKM_MD2_RSA_PKCS

CKM_MD5_RSA_PKCS

CKM_SHA1_RSA_PKCS

CKM_SHA224_RSA_PKCS

CKM_SHA256_RSA_PKCS

CKM_SHA384_RSA_PKCS

CKM_SHA512_RSA_PKCS

CKM_RIPEMD128_RSA_PKCS

CKM_RIPEMD160_RSA_PKCS

CKM_RSA_PKCS_OAEP

CKM_RSA_X9_31_KEY_PAIR_GEN

CKM_RSA_X9_31

CKM_SHA1_RSA_X9_31

CKM_RSA_PKCS_PSS

CKM_SHA1_RSA_PKCS_PSS

CKM_SHA224_RSA_PKCS_PSS

CKM_SHA256_RSA_PKCS_PSS

CKM_SHA512_RSA_PKCS_PSS

CKM_SHA384_RSA_PKCS_PSS

CKM_RSA_PKCS_TPM_1_1

CKM_RSA_PKCS_OAEP_TPM_1_1

CKM_RSA_AES_KEY_WRAP

CKM_SHA3_224_RSA_PKCS

CKM_SHA3_256_RSA_PKCS

CKM_SHA3_384_RSA_PKCS

CKM_SHA3_512_RSA_PKCS

CKM_SHA3_224_RSA_PKCS_PSS

CKM_SHA3_256_RSA_PKCS_PSS

CKM_SHA3_384_RSA_PKCS_PSS

CKM_SHA3_512_RSA_PKCS_PSS

2.1.2 RSA public key objects

RSA public key objects (object class CKO_PUBLIC_KEY, key type CKK_RSA) hold RSA public keys. The following table defines the RSA public key object attributes, in addition to the common attributes defined for this object class:

Table 2, RSA Public Key Object Attributes

Attribute	Data type	Meaning
CKA_MODULUS^1,4	Big integer	Modulus n
CKA_MODULUS_BITS^2,3	CK_ULONG	Length in bits of modulus n
CKA_PUBLIC_EXPONENT¹	Big integer	Public exponent e

^{- Refer to [PKCS11-Base]
table 11 for footnotes}

Depending on the token, there may be limits on the length of key components. See PKCS #1 for more information on RSA keys.

The following is a sample template for creating an RSA public key object:

CK_OBJECT_CLASS class = CKO_PUBLIC_KEY;

CK_KEY_TYPE keyType = CKK_RSA;

CK_UTF8CHAR label[] = “An RSA public key object”;

CK_BYTE modulus[] = {...};

CK_BYTE exponent[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_WRAP, &true, sizeof(true)},

{CKA_ENCRYPT, &true, sizeof(true)},

{CKA_MODULUS, modulus, sizeof(modulus)},

{CKA_PUBLIC_EXPONENT, exponent, sizeof(exponent)}

};

2.1.3 RSA private key objects

RSA private key objects (object class CKO_PRIVATE_KEY, key type CKK_RSA) hold RSA private keys. The following table defines the RSA private key object attributes, in addition to the common attributes defined for this object class:

Table 3, RSA Private Key Object Attributes

Attribute	Data type	Meaning
CKA_MODULUS^1,4,6	Big integer	Modulus n
CKA_PUBLIC_EXPONENT^4,6	Big integer	Public exponent e
CKA_PRIVATE_EXPONENT^1,4,6,7	Big integer	Private exponent d
CKA_PRIME_1^4,6,7	Big integer	Prime p
CKA_PRIME_2^4,6,7	Big integer	Prime q
CKA_EXPONENT_1^4,6,7	Big integer	Private exponent d modulo p-1
CKA_EXPONENT_2^4,6,7	Big integer	Private exponent d modulo q-1
CKA_COEFFICIENT^4,6,7	Big integer	CRT coefficient q^-1 mod p

^{- Refer
to [PKCS11-Base] table 11 for footnotes}

Depending on the token, there may be limits on the length of the key components. See PKCS #1 for more information on RSA keys.

Tokens vary in what they actually store for RSA private keys. Some tokens store all of the above attributes, which can assist in performing rapid RSA computations. Other tokens might store only the CKA_MODULUS and CKA_PRIVATE_EXPONENT values. Effective with version 2.40, tokens MUST also store CKA_PUBLIC_EXPONENT. This permits the retrieval of sufficient data to reconstitute the associated public key.

Because of this, Cryptoki is flexible in dealing with RSA private key objects. When a token generates an RSA private key, it stores whichever of the fields in Table 3 it keeps track of. Later, if an application asks for the values of the key’s various attributes, Cryptoki supplies values only for attributes whose values it can obtain (i.e., if Cryptoki is asked for the value of an attribute it cannot obtain, the request fails). Note that a Cryptoki implementation may or may not be able and/or willing to supply various attributes of RSA private keys which are not actually stored on the token. E.g., if a particular token stores values only for the CKA_PRIVATE_EXPONENT, CKA_PRIME_1, and CKA_PRIME_2 attributes, then Cryptoki is certainly able to report values for all the attributes above (since they can all be computed efficiently from these three values). However, a Cryptoki implementation may or may not actually do this extra computation. The only attributes from Table 3 for which a Cryptoki implementation is required to be able to return values are CKA_MODULUS and CKA_PRIVATE_EXPONENT.

If an RSA private key object is created on a token, and more attributes from Table 3 are supplied to the object creation call than are supported by the token, the extra attributes are likely to be thrown away. If an attempt is made to create an RSA private key object on a token with insufficient attributes for that particular token, then the object creation call fails and returns CKR_TEMPLATE_INCOMPLETE.

Note that when generating an RSA private key, there is no CKA_MODULUS_BITS attribute specified. This is because RSA private keys are only generated as part of an RSA key pair, and the CKA_MODULUS_BITS attribute for the pair is specified in the template for the RSA public key.

The following is a sample template for creating an RSA private key object:

CK_OBJECT_CLASS class = CKO_PRIVATE_KEY;

CK_KEY_TYPE keyType = CKK_RSA;

CK_UTF8CHAR label[] = “An RSA private key object”;

CK_BYTE subject[] = {...};

CK_BYTE id[] = {123};

CK_BYTE modulus[] = {...};

CK_BYTE publicExponent[] = {...};

CK_BYTE privateExponent[] = {...};

CK_BYTE prime1[] = {...};

CK_BYTE prime2[] = {...};

CK_BYTE exponent1[] = {...};

CK_BYTE exponent2[] = {...};

CK_BYTE coefficient[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_SUBJECT, subject, sizeof(subject)},

{CKA_ID, id, sizeof(id)},

{CKA_SENSITIVE, &true, sizeof(true)},

{CKA_DECRYPT, &true, sizeof(true)},

{CKA_SIGN, &true, sizeof(true)},

{CKA_MODULUS, modulus, sizeof(modulus)},

{CKA_PUBLIC_EXPONENT, publicExponent, sizeof(publicExponent)},

{CKA_PRIVATE_EXPONENT, privateExponent, sizeof(privateExponent)},

{CKA_PRIME_1, prime1, sizeof(prime1)},

{CKA_PRIME_2, prime2, sizeof(prime2)},

{CKA_EXPONENT_1, exponent1, sizeof(exponent1)},

{CKA_EXPONENT_2, exponent2, sizeof(exponent2)},

{CKA_COEFFICIENT, coefficient, sizeof(coefficient)}

};

2.1.4 PKCS #1 RSA key pair generation

The PKCS #1 RSA key pair generation mechanism, denoted CKM_RSA_PKCS_KEY_PAIR_GEN, is a key pair generation mechanism based on the RSA public-key cryptosystem, as defined in PKCS #1.

It does not have a parameter.

The mechanism generates RSA public/private key pairs with a particular modulus length in bits and public exponent, as specified in the CKA_MODULUS_BITS and CKA_PUBLIC_EXPONENT attributes of the template for the public key. The CKA_PUBLIC_EXPONENT may be omitted in which case the mechanism shall supply the public exponent attribute using the default value of 0x10001 (65537). Specific implementations may use a random value or an alternative default if 0x10001 cannot be used by the token.

Note: Implementations strictly compliant with version 2.11 or prior versions may generate an error if this attribute is omitted from the template. Experience has shown that many implementations of 2.11 and prior did allow the CKA_PUBLIC_EXPONENT attribute to be omitted from the template, and behaved as described above. The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, CKA_MODULUS, and CKA_PUBLIC_EXPONENT attributes to the new public key. CKA_PUBLIC_EXPONENT will be copied from the template if supplied. CKR_TEMPLATE_INCONSISTENT shall be returned if the implementation cannot use the supplied exponent value. It contributes the CKA_CLASS and CKA_KEY_TYPE attributes to the new private key; it may also contribute some of the following attributes to the new private key: CKA_MODULUS, CKA_PUBLIC_EXPONENT, CKA_PRIVATE_EXPONENT, CKA_PRIME_1, CKA_PRIME_2, CKA_EXPONENT_1, CKA_EXPONENT_2, CKA_COEFFICIENT. Other attributes supported by the RSA public and private key types (specifically, the flags indicating which functions the keys support) may also be specified in the templates for the keys, or else are assigned default initial values.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.5 X9.31 RSA key pair generation

The X9.31 RSA key pair generation mechanism, denoted CKM_RSA_X9_31_KEY_PAIR_GEN, is a key pair generation mechanism based on the RSA public-key cryptosystem, as defined in X9.31.

It does not have a parameter.

The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, CKA_MODULUS, and CKA_PUBLIC_EXPONENT attributes to the new public key. It contributes the CKA_CLASS and CKA_KEY_TYPE attributes to the new private key; it may also contribute some of the following attributes to the new private key: CKA_MODULUS, CKA_PUBLIC_EXPONENT, CKA_PRIVATE_EXPONENT, CKA_PRIME_1, CKA_PRIME_2, CKA_EXPONENT_1, CKA_EXPONENT_2, CKA_COEFFICIENT. Other attributes supported by the RSA public and private key types (specifically, the flags indicating which functions the keys support) may also be specified in the templates for the keys, or else are assigned default initial values. Unlike the CKM_RSA_PKCS_KEY_PAIR_GEN mechanism, this mechanism is guaranteed to generate p and q values, CKA_PRIME_1 and CKA_PRIME_2 respectively, that meet the strong primes requirement of X9.31.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.6 PKCS #1 v1.5 RSA

The PKCS #1 v1.5 RSA mechanism, denoted CKM_RSA_PKCS, is a multi-purpose mechanism based on the RSA public-key cryptosystem and the block formats initially defined in PKCS #1 v1.5. It supports single-part encryption and decryption; single-part signatures and verification with and without message recovery; key wrapping; and key unwrapping. This mechanism corresponds only to the part of PKCS #1 v1.5 that involves RSA; it does not compute a message digest or a DigestInfo encoding as specified for the md2withRSAEncryption and md5withRSAEncryption algorithms in PKCS #1 v1.5 .

This mechanism does not have a parameter.

This mechanism can wrap and unwrap any secret key of appropriate length. Of course, a particular token may not be able to wrap/unwrap every appropriate-length secret key that it supports. For wrapping, the “input” to the encryption operation is the value of the CKA_VALUE attribute of the key that is wrapped; similarly for unwrapping. The mechanism does not wrap the key type or any other information about the key, except the key length; the application must convey these separately. In particular, the mechanism contributes only the CKA_CLASS and CKA_VALUE (and CKA_VALUE_LEN, if the key has it) attributes to the recovered key during unwrapping; other attributes must be specified in the template.

Constraints on key types and the length of the data are summarized in the following table. For encryption, decryption, signatures and signature verification, the input and output data may begin at the same location in memory. In the table, k is the length in bytes of the RSA modulus.

Table 4, PKCS #1 v1.5 RSA: Key And Data Length

Function	Key type	Input length	Output length	Comments
C_Encrypt¹	RSA public key	£ k-11	k	block type 02
C_Decrypt¹	RSA private key	k	£ k-11	block type 02
C_Sign¹	RSA private key	£ k-11	k	block type 01
C_SignRecover	RSA private key	£ k-11	k	block type 01
C_Verify¹	RSA public key	£ k-11, k²	N/A	block type 01
C_VerifyRecover	RSA public key	k	£ k-11	block type 01
C_WrapKey	RSA public key	£ k-11	k	block type 02
C_UnwrapKey	RSA private key	k	£ k-11	block type 02

¹ Single-part operations only.

2 Data length, signature length.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.7 PKCS #1 RSA OAEP mechanism parameters

¨ CK_RSA_PKCS_MGF_TYPE; CK_RSA_PKCS_MGF_TYPE_PTR

CK_RSA_PKCS_MGF_TYPE is used to indicate the Message Generation Function (MGF) applied to a message block when formatting a message block for the PKCS #1 OAEP encryption scheme or the PKCS #1 PSS signature scheme. It is defined as follows:

typedef CK_ULONG CK_RSA_PKCS_MGF_TYPE;

The following MGFs are defined in PKCS #1. The following table lists the defined functions.

Table 5, PKCS #1 Mask Generation Functions

Source Identifier	Value
CKG_MGF1_SHA1	0x00000001UL
CKG_MGF1_SHA224	0x00000005UL
CKG_MGF1_SHA256	0x00000002UL
CKG_MGF1_SHA384	0x00000003UL
CKG_MGF1_SHA512	0x00000004UL
CKG_MGF1_SHA3_224	0x00000006UL
CKG_MGF1_SHA3_256	0x00000007UL
CKG_MGF1_SHA3_384	0x00000008UL
CKG_MGF1_SHA3_512	0x00000009UL

CK_RSA_PKCS_MGF_TYPE_PTR is a pointer to a CK_RSA_PKCS_ MGF_TYPE.

¨ CK_RSA_PKCS_OAEP_SOURCE_TYPE; CK_RSA_PKCS_OAEP_SOURCE_TYPE_PTR

CK_RSA_PKCS_OAEP_SOURCE_TYPE is used to indicate the source of the encoding parameter when formatting a message block for the PKCS #1 OAEP encryption scheme. It is defined as follows:

typedef CK_ULONG CK_RSA_PKCS_OAEP_SOURCE_TYPE;

The following encoding parameter sources are defined in PKCS #1. The following table lists the defined sources along with the corresponding data type for the pSourceData field in the CK_RSA_PKCS_OAEP_PARAMS structure defined below.

Table 6, PKCS #1 RSA OAEP: Encoding parameter sources

Source Identifier	Value	Data Type
CKZ_DATA_SPECIFIED	0x00000001UL	Array of CK_BYTE containing the value of the encoding parameter. If the parameter is empty, pSourceData must be NULL and ulSourceDataLen must be zero.

CK_RSA_PKCS_OAEP_SOURCE_TYPE_PTR is a pointer to a CK_RSA_PKCS_OAEP_SOURCE_TYPE.

¨ CK_RSA_PKCS_OAEP_PARAMS; CK_RSA_PKCS_OAEP_PARAMS_PTR

CK_RSA_PKCS_OAEP_PARAMS is a structure that provides the parameters to the CKM_RSA_PKCS_OAEP mechanism. The structure is defined as follows:

typedef struct CK_RSA_PKCS_OAEP_PARAMS {

CK_MECHANISM_TYPE hashAlg;

CK_RSA_PKCS_MGF_TYPE mgf;

CK_RSA_PKCS_OAEP_SOURCE_TYPE source;

CK_VOID_PTR pSourceData;

CK_ULONG ulSourceDataLen;

} CK_RSA_PKCS_OAEP_PARAMS;

The fields of the structure have the following meanings:

hashAlg mechanism ID of the message digest algorithm used to calculate the digest of the encoding parameter

mgf mask generation function to use on the encoded block

source source of the encoding parameter

pSourceData data used as the input for the encoding parameter source

ulSourceDataLen length of the encoding parameter source input

CK_RSA_PKCS_OAEP_PARAMS_PTR is a pointer to a CK_RSA_PKCS_OAEP_PARAMS.

2.1.8 PKCS #1 RSA OAEP

The PKCS #1 RSA OAEP mechanism, denoted CKM_RSA_PKCS_OAEP, is a multi-purpose mechanism based on the RSA public-key cryptosystem and the OAEP block format defined in PKCS #1. It supports single-part encryption and decryption; key wrapping; and key unwrapping.

It has a parameter, a CK_RSA_PKCS_OAEP_PARAMS structure.

Constraints on key types and the length of the data are summarized in the following table. For encryption and decryption, the input and output data may begin at the same location in memory. In the table, k is the length in bytes of the RSA modulus, and hLen is the output length of the message digest algorithm specified by the hashAlg field of the CK_RSA_PKCS_OAEP_PARAMS structure.

Table 7, PKCS #1 RSA OAEP: Key And Data Length

Function	Key type	Input length	Output length
C_Encrypt¹	RSA public key	£ k-2-2hLen	k
C_Decrypt¹	RSA private key	k	£ k-2-2hLen
C_WrapKey	RSA public key	£ k-2-2hLen	k
C_UnwrapKey	RSA private key	k	£ k-2-2hLen

¹ Single-part operations only.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.9 PKCS #1 RSA PSS mechanism parameters

¨ CK_RSA_PKCS_PSS_PARAMS; CK_RSA_PKCS_PSS_PARAMS_PTR

CK_RSA_PKCS_PSS_PARAMS is a structure that provides the parameters to the CKM_RSA_PKCS_PSS mechanism. The structure is defined as follows:

typedef struct CK_RSA_PKCS_PSS_PARAMS {

CK_MECHANISM_TYPE hashAlg;

CK_RSA_PKCS_MGF_TYPE mgf;

CK_ULONG sLen;

} CK_RSA_PKCS_PSS_PARAMS;

The fields of the structure have the following meanings:

hashAlg hash algorithm used in the PSS encoding; if the signature mechanism does not include message hashing, then this value must be the mechanism used by the application to generate the message hash; if the signature mechanism includes hashing, then this value must match the hash algorithm indicated by the signature mechanism

mgf mask generation function to use on the encoded block

sLen length, in bytes, of the salt value used in the PSS encoding; typical values are the length of the message hash and zero

CK_RSA_PKCS_PSS_PARAMS_PTR is a pointer to a CK_RSA_PKCS_PSS_PARAMS.

2.1.10 PKCS #1 RSA PSS

The PKCS #1 RSA PSS mechanism, denoted CKM_RSA_PKCS_PSS, is a mechanism based on the RSA public-key cryptosystem and the PSS block format defined in PKCS #1. It supports single-part signature generation and verification without message recovery. This mechanism corresponds only to the part of PKCS #1 that involves block formatting and RSA, given a hash value; it does not compute a hash value on the message to be signed.

It has a parameter, a CK_RSA_PKCS_PSS_PARAMS structure. The sLen field must be less than or equal to k*-2-hLen and hLen is the length of the input to the C_Sign or C_Verify function. k* is the length in bytes of the RSA modulus, except if the length in bits of the RSA modulus is one more than a multiple of 8, in which case k* is one less than the length in bytes of the RSA modulus.

Constraints on key types and the length of the data are summarized in the following table. In the table, k is the length in bytes of the RSA.

Table 8, PKCS #1 RSA PSS: Key And Data Length

Function	Key type	Input length	Output length
C_Sign¹	RSA private key	hLen	k
C_Verify¹	RSA public key	hLen, k	N/A

¹ Single-part operations only.

2 Data length, signature length.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.11 ISO/IEC 9796 RSA

The ISO/IEC 9796 RSA mechanism, denoted CKM_RSA_9796, is a mechanism for single-part signatures and verification with and without message recovery based on the RSA public-key cryptosystem and the block formats defined in ISO/IEC 9796 and its annex A.

This mechanism processes only byte strings, whereas ISO/IEC 9796 operates on bit strings. Accordingly, the following transformations are performed:

· Data is converted between byte and bit string formats by interpreting the most-significant bit of the leading byte of the byte string as the leftmost bit of the bit string, and the least-significant bit of the trailing byte of the byte string as the rightmost bit of the bit string (this assumes the length in bits of the data is a multiple of 8).

· A signature is converted from a bit string to a byte string by padding the bit string on the left with 0 to 7 zero bits so that the resulting length in bits is a multiple of 8, and converting the resulting bit string as above; it is converted from a byte string to a bit string by converting the byte string as above, and removing bits from the left so that the resulting length in bits is the same as that of the RSA modulus.

This mechanism does not have a parameter.

Constraints on key types and the length of input and output data are summarized in the following table. In the table, k is the length in bytes of the RSA modulus.

Table 9, ISO/IEC 9796 RSA: Key And Data Length

Function	Key type	Input length	Output length
C_Sign¹	RSA private key	£ ëk/2û	k
C_SignRecover	RSA private key	£ ëk/2û	k
C_Verify¹	RSA public key	£ ëk/2û, k²	N/A
C_VerifyRecover	RSA public key	k	£ ëk/2û

¹ Single-part operations only.

2 Data length, signature length.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.12 X.509 (raw) RSA

The X.509 (raw) RSA mechanism, denoted CKM_RSA_X_509, is a multi-purpose mechanism based on the RSA public-key cryptosystem. It supports single-part encryption and decryption; single-part signatures and verification with and without message recovery; key wrapping; and key unwrapping. All these operations are based on so-called “raw” RSA, as assumed in X.509.

“Raw” RSA as defined here encrypts a byte string by converting it to an integer, most-significant byte first, applying “raw” RSA exponentiation, and converting the result to a byte string, most-significant byte first. The input string, considered as an integer, must be less than the modulus; the output string is also less than the modulus.

This mechanism does not have a parameter.

This mechanism can wrap and unwrap any secret key of appropriate length. Of course, a particular token may not be able to wrap/unwrap every appropriate-length secret key that it supports. For wrapping, the “input” to the encryption operation is the value of the CKA_VALUE attribute of the key that is wrapped; similarly for unwrapping. The mechanism does not wrap the key type, key length, or any other information about the key; the application must convey these separately, and supply them when unwrapping the key.

Unfortunately, X.509 does not specify how to perform padding for RSA encryption. For this mechanism, padding should be performed by prepending plaintext data with 0-valued bytes. In effect, to encrypt the sequence of plaintext bytes b₁ b₂ … b_n (n £ k), Cryptoki forms P=2^n-1b₁+2^n-2b₂+…+b_n. This number must be less than the RSA modulus. The k-byte ciphertext (k is the length in bytes of the RSA modulus) is produced by raising P to the RSA public exponent modulo the RSA modulus. Decryption of a k-byte ciphertext C is accomplished by raising C to the RSA private exponent modulo the RSA modulus, and returning the resulting value as a sequence of exactly k bytes. If the resulting plaintext is to be used to produce an unwrapped key, then however many bytes are specified in the template for the length of the key are taken from the end of this sequence of bytes.

Technically, the above procedures may differ very slightly from certain details of what is specified in X.509.

Executing cryptographic operations using this mechanism can result in the error returns CKR_DATA_INVALID (if plaintext is supplied which has the same length as the RSA modulus and is numerically at least as large as the modulus) and CKR_ENCRYPTED_DATA_INVALID (if ciphertext is supplied which has the same length as the RSA modulus and is numerically at least as large as the modulus).

Constraints on key types and the length of input and output data are summarized in the following table. In the table, k is the length in bytes of the RSA modulus.

Table 10, X.509 (Raw) RSA: Key And Data Length

Function	Key type	Input length	Output length
C_Encrypt¹	RSA public key	£ k	k
C_Decrypt¹	RSA private key	k	k
C_Sign¹	RSA private key	£ k	k
C_SignRecover	RSA private key	£ k	k
C_Verify¹	RSA public key	£ k, k²	N/A
C_VerifyRecover	RSA public key	k	k
C_WrapKey	RSA public key	£ k	k
C_UnwrapKey	RSA private key	k	£ k (specified in template)

¹ Single-part operations only.

2 Data length, signature length.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

This mechanism is intended for compatibility with applications that do not follow the PKCS #1 or ISO/IEC 9796 block formats.

2.1.13 ANSI X9.31 RSA

The ANSI X9.31 RSA mechanism, denoted CKM_RSA_X9_31, is a mechanism for single-part signatures and verification without message recovery based on the RSA public-key cryptosystem and the block formats defined in ANSI X9.31.

This mechanism applies the header and padding fields of the hash encapsulation. The trailer field must be applied by the application.

This mechanism processes only byte strings, whereas ANSI X9.31 operates on bit strings. Accordingly, the following transformations are performed:

This mechanism does not have a parameter.

Constraints on key types and the length of input and output data are summarized in the following table. In the table, k is the length in bytes of the RSA modulus. For all operations, the k value must be at least 128 and a multiple of 32 as specified in ANSI X9.31.

Table 11, ANSI X9.31 RSA: Key And Data Length

Function	Key type	Input length	Output length
C_Sign¹	RSA private key	£ k-2	k
C_Verify¹	RSA public key	£ k-2, k²	N/A

¹ Single-part operations only.

2 Data length, signature length.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.14 PKCS #1 v1.5 RSA signature with MD2, MD5, SHA-1, SHA-256, SHA-384, SHA-512, RIPE-MD 128 or RIPE-MD 160

The PKCS #1 v1.5 RSA signature with MD2 mechanism, denoted CKM_MD2_RSA_PKCS, performs single- and multiple-part digital signatures and verification operations without message recovery. The operations performed are as described initially in PKCS #1 v1.5 with the object identifier md2WithRSAEncryption, and as in the scheme RSASSA-PKCS1-v1_5 in the current version of PKCS #1, where the underlying hash function is MD2.

Similarly, the PKCS #1 v1.5 RSA signature with MD5 mechanism, denoted CKM_MD5_RSA_PKCS, performs the same operations described in PKCS #1 with the object identifier md5WithRSAEncryption. The PKCS #1 v1.5 RSA signature with SHA-1 mechanism, denoted CKM_SHA1_RSA_PKCS, performs the same operations, except that it uses the hash function SHA-1 with object identifier sha1WithRSAEncryption.

Likewise, the PKCS #1 v1.5 RSA signature with SHA-256, SHA-384, and SHA-512 mechanisms, denoted CKM_SHA256_RSA_PKCS, CKM_SHA384_RSA_PKCS, and CKM_SHA512_RSA_PKCS respectively, perform the same operations using the SHA-256, SHA-384 and SHA-512 hash functions with the object identifiers sha256WithRSAEncryption, sha384WithRSAEncryption and sha512WithRSAEncryption respectively.

The PKCS #1 v1.5 RSA signature with RIPEMD-128 or RIPEMD-160, denoted CKM_RIPEMD128_RSA_PKCS and CKM_RIPEMD160_RSA_PKCS respectively, perform the same operations using the RIPE-MD 128 and RIPE-MD 160 hash functions.

None of these mechanisms has a parameter.

Constraints on key types and the length of the data for these mechanisms are summarized in the following table. In the table, k is the length in bytes of the RSA modulus. For the PKCS #1 v1.5 RSA signature with MD2 and PKCS #1 v1.5 RSA signature with MD5 mechanisms, k must be at least 27; for the PKCS #1 v1.5 RSA signature with SHA-1 mechanism, k must be at least 31, and so on for other underlying hash functions, where the minimum is always 11 bytes more than the length of the hash value.

Table 12, PKCS #1 v1.5 RSA Signatures with Various Hash Functions: Key And Data Length

Function	Key type	Input length	Output length	Comments
C_Sign	RSA private key	any	k	block type 01
C_Verify	RSA public key	any, k²	N/A	block type 01

² Data length, signature length.

For these mechanisms, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.15 PKCS #1 v1.5 RSA signature with SHA-224

The PKCS #1 v1.5 RSA signature with SHA-224 mechanism, denoted CKM_SHA224_RSA_PKCS, performs similarly as the other CKM_SHAX_RSA_PKCS mechanisms but uses the SHA-224 hash function.

2.1.16 PKCS #1 RSA PSS signature with SHA-224

The PKCS #1 RSA PSS signature with SHA-224 mechanism, denoted CKM_SHA224_RSA_PKCS_PSS, performs similarly as the other CKM_SHAX_RSA_ PKCS_PSS mechanisms but uses the SHA-224 hash function.

2.1.17 PKCS #1 RSA PSS signature with SHA-1, SHA-256, SHA-384 or SHA-512

The PKCS #1 RSA PSS signature with SHA-1 mechanism, denoted CKM_SHA1_RSA_PKCS_PSS, performs single- and multiple-part digital signatures and verification operations without message recovery. The operations performed are as described in PKCS #1 with the object identifier id-RSASSA-PSS, i.e., as in the scheme RSASSA-PSS in PKCS #1 where the underlying hash function is SHA-1.

The PKCS #1 RSA PSS signature with SHA-256, SHA-384, and SHA-512 mechanisms, denoted CKM_SHA256_RSA_PKCS_PSS, CKM_SHA384_RSA_PKCS_PSS, and CKM_SHA512_RSA_PKCS_PSS respectively, perform the same operations using the SHA-256, SHA-384 and SHA-512 hash functions.

The mechanisms have a parameter, a CK_RSA_PKCS_PSS_PARAMS structure. The sLen field must be less than or equal to k*-2-hLen where hLen is the length in bytes of the hash value. k* is the length in bytes of the RSA modulus, except if the length in bits of the RSA modulus is one more than a multiple of 8, in which case k* is one less than the length in bytes of the RSA modulus.

Constraints on key types and the length of the data are summarized in the following table. In the table, k is the length in bytes of the RSA modulus.

Table 13, PKCS #1 RSA PSS Signatures with Various Hash Functions: Key And Data Length

Function	Key type	Input length	Output length
C_Sign	RSA private key	any	k
C_Verify	RSA public key	any, k²	N/A

² Data length, signature length.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.18 PKCS #1 v1.5 RSA signature with SHA3

The PKCS #1 v1.5 RSA signature with SHA3-224, SHA3-256, SHA3-384, SHA3-512 mechanisms, denoted CKM_SHA3_224_RSA_PKCS, CKM_SHA3_256_RSA_PKCS, CKM_SHA3_384_RSA_PKCS, and CKM_SHA3_512_RSA_PKCS respectively, performs similarly as the other CKM_SHAX_RSA_PKCS mechanisms but uses the corresponding SHA3 hash functions.

2.1.19 PKCS #1 RSA PSS signature with SHA3

The PKCS #1 RSA PSS signature with SHA3-224, SHA3-256, SHA3-384, SHA3-512 mechanisms, denoted CKM_SHA3_224_RSA_PKCS_PSS, CKM_SHA3_256_RSA_PKCS_PSS, CKM_SHA3_384_RSA_PKCS_PSS, and CKM_SHA3_512_RSA_PKCS_PSS respectively, performs similarly as the other CKM_SHAX_RSA_PKCS_PSS mechanisms but uses the corresponding SHA-3 hash functions.

2.1.20 ANSI X9.31 RSA signature with SHA-1

The ANSI X9.31 RSA signature with SHA-1 mechanism, denoted CKM_SHA1_RSA_X9_31, performs single- and multiple-part digital signatures and verification operations without message recovery. The operations performed are as described in ANSI X9.31.

This mechanism does not have a parameter.

Constraints on key types and the length of the data for these mechanisms are summarized in the following table. In the table, k is the length in bytes of the RSA modulus. For all operations, the k value must be at least 128 and a multiple of 32 as specified in ANSI X9.31.

Table 14, ANSI X9.31 RSA Signatures with SHA-1: Key And Data Length

Function	Key type	Input length	Output length
C_Sign	RSA private key	any	k
C_Verify	RSA public key	any, k²	N/A

² Data length, signature length.

For these mechanisms, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.21 TPM 1.1b and TPM 1.2 PKCS #1 v1.5 RSA

The TPM 1.1b and TPM 1.2 PKCS #1 v1.5 RSA mechanism, denoted CKM_RSA_PKCS_TPM_1_1, is a multi-use mechanism based on the RSA public-key cryptosystem and the block formats initially defined in PKCS #1 v1.5, with additional formatting rules defined in TCPA TPM Specification Version 1.1b. Additional formatting rules remained the same in TCG TPM Specification 1.2 The mechanism supports single-part encryption and decryption; key wrapping; and key unwrapping.

This mechanism does not have a parameter. It differs from the standard PKCS#1 v1.5 RSA encryption mechanism in that the plaintext is wrapped in a TCPA_BOUND_DATA (TPM_BOUND_DATA for TPM 1.2) structure before being submitted to the PKCS#1 v1.5 encryption process. On encryption, the version field of the TCPA_BOUND_DATA (TPM_BOUND_DATA for TPM 1.2) structure must contain 0x01, 0x01, 0x00, 0x00. On decryption, any structure of the form 0x01, 0x01, 0xXX, 0xYY may be accepted.

Table 15, TPM 1.1b and TPM 1.2 PKCS #1 v1.5 RSA: Key And Data Length

Function	Key type	Input length	Output length
C_Encrypt¹	RSA public key	£ k-11-5	k
C_Decrypt¹	RSA private key	k	£ k-11-5
C_WrapKey	RSA public key	£ k-11-5	k
C_UnwrapKey	RSA private key	k	£ k-11-5

¹ Single-part operations only.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.22 TPM 1.1b and TPM 1.2 PKCS #1 RSA OAEP

The TPM 1.1b and TPM 1.2 PKCS #1 RSA OAEP mechanism, denoted CKM_RSA_PKCS_OAEP_TPM_1_1, is a multi-purpose mechanism based on the RSA public-key cryptosystem and the OAEP block format defined in PKCS #1, with additional formatting defined in TCPA TPM Specification Version 1.1b. Additional formatting rules remained the same in TCG TPM Specification 1.2. The mechanism supports single-part encryption and decryption; key wrapping; and key unwrapping.

This mechanism does not have a parameter. It differs from the standard PKCS#1 OAEP RSA encryption mechanism in that the plaintext is wrapped in a TCPA_BOUND_DATA (TPM_BOUND_DATA for TPM 1.2) structure before being submitted to the encryption process and that all of the values of the parameters that are passed to a standard CKM_RSA_PKCS_OAEP operation are fixed. On encryption, the version field of the TCPA_BOUND_DATA (TPM_BOUND_DATA for TPM 1.2) structure must contain 0x01, 0x01, 0x00, 0x00. On decryption, any structure of the form 0x01, 0x01, 0xXX, 0xYY may be accepted.

Table 16, TPM 1.1b and TPM 1.2 PKCS #1 RSA OAEP: Key And Data Length

Function	Key type	Input length	Output length
C_Encrypt¹	RSA public key	£ k-2-40-5	k
C_Decrypt¹	RSA private key	k	£ k-2-40-5
C_WrapKey	RSA public key	£ k-2-40-5	k
C_UnwrapKey	RSA private key	k	£ k-2-40-5

¹ Single-part operations only.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of RSA modulus sizes, in bits.

2.1.23 RSA AES KEY WRAP

The RSA AES key wrap mechanism, denoted CKM_RSA_AES_KEY_WRAP, is a mechanism based on the RSA public-key cryptosystem and the AES key wrap mechanism. It supports single-part key wrapping; and key unwrapping.

It has a parameter, a CK_RSA_AES_KEY_WRAP_PARAMS structure.

The mechanism can wrap and unwrap a target asymmetric key of any length and type using an RSA key.

- A temporary AES key is used for wrapping the target key using CKM_AES_KEY_WRAP_KWP mechanism.

- The temporary AES key is wrapped with the wrapping RSA key using CKM_RSA_PKCS_OAEP mechanism.

For wrapping, the mechanism -

Generates a temporary random AES key of ulAESKeyBits length. This key is not accessible to the user - no handle is returned.
Wraps the AES key with the wrapping RSA key using CKM_RSA_PKCS_OAEP with parameters of OAEPParams.
Wraps the target key with the temporary AES key using CKM_AES_KEY_WRAP_KWP ([AES KEYWRAP] section 6.3).
Zeroizes the temporary AES key
Concatenates two wrapped keys and outputs the concatenated blob. The first is the wrapped AES key, and the second is the wrapped target key.

The recommended format for an asymmetric target key being wrapped is as a PKCS8 PrivateKeyInfo

The use of Attributes in the PrivateKeyInfo structure is OPTIONAL. In case of conflicts between the object attribute template, and Attributes in the PrivateKeyInfo structure, an error should be thrown

For unwrapping, the mechanism -

Splits the input into two parts. The first is the wrapped AES key, and the second is the wrapped target key. The length of the first part is equal to the length of the unwrapping RSA key.
Un-wraps the temporary AES key from the first part with the private RSA key using CKM_RSA_PKCS_OAEP with parameters of OAEPParams.
Un-wraps the target key from the second part with the temporary AES key using CKM_AES_KEY_WRAP_KWP ([AES KEYWRAP] section 6.3).
Zeroizes the temporary AES key.
Returns the handle to the newly unwrapped target key.

Table 17, CKM_RSA_AES_KEY_WRAP Mechanisms vs. Functions

	Functions
Mechanism	Encrypt & Decrypt	Sign & Verify	SR & VR1	Digest	Gen. Key/ Key Pair	Wrap & Unwrap	Derive
CKM_RSA_AES_KEY_WRAP						ü
1SR = SignRecover, VR = VerifyRecover

2.1.24 RSA AES KEY WRAP mechanism parameters

¨ CK_RSA_AES_KEY_WRAP_PARAMS; CK_RSA_AES_KEY_WRAP_PARAMS_PTR

CK_RSA_AES_KEY_WRAP_PARAMS is a structure that provides the parameters to the CKM_RSA_AES_KEY_WRAP mechanism. It is defined as follows:

typedef struct CK_RSA_AES_KEY_WRAP_PARAMS {

CK_ULONG ulAESKeyBits;

CK_RSA_PKCS_OAEP_PARAMS_PTR pOAEPParams;

} CK_RSA_AES_KEY_WRAP_PARAMS;

The fields of the structure have the following meanings:

ulAESKeyBits length of the temporary AES key in bits. Can be only 128, 192 or 256.

pOAEPParams pointer to the parameters of the temporary AES key wrapping. See also the description of PKCS #1 RSA OAEP mechanism parameters.

CK_RSA_AES_KEY_WRAP_PARAMS_PTR is a pointer to a CK_RSA_AES_KEY_WRAP_PARAMS.

2.1.25 FIPS 186-4

When CKM_RSA_PKCS is operated in FIPS mode, the length of the modulus SHALL only be 1024, 2048, or 3072 bits.

2.2 DSA

Table 18, DSA Mechanisms vs. Functions

	Functions
Mechanism	Encrypt & Decrypt	Sign & Verify	SR & VR¹	Digest	Gen. Key/ Key Pair	Wrap & Unwrap	Derive
CKM_DSA_KEY_PAIR_GEN					ü
CKM_DSA_PARAMETER_GEN					ü
CKM_DSA_PROBABILISTIC_PARAMETER_GEN					ü
CKM_DSA_SHAWE_TAYLOR_PARAMETER_GEN					ü
CKM_DSA_FIPS_G_GEN					ü
CKM_DSA		ü²
CKM_DSA_SHA1		ü
CKM_DSA_SHA224		ü
CKM_DSA_SHA256		ü
CKM_DSA_SHA384		ü
CKM_DSA_SHA512		ü
CKM_DSA_SHA3_224		ü
CKM_DSA_SHA3_256		ü
CKM_DSA_SHA3_384		ü
CKM_DSA_SHA3_512		ü

2.2.1 Definitions

This section defines the key type “CKK_DSA” for type CK_KEY_TYPE as used in the CKA_KEY_TYPE attribute of DSA key objects.

Mechanisms:

CKM_DSA_KEY_PAIR_GEN

CKM_DSA

CKM_DSA_SHA1

CKM_DSA_SHA224

CKM_DSA_SHA256

CKM_DSA_SHA384

CKM_DSA_SHA512

CKM_DSA_SHA3_224

CKM_DSA_SHA3_256

CKM_DSA_SHA3_384

CKM_DSA_SHA3_512

CKM_DSA_PARAMETER_GEN

CKM_DSA_PROBABILISTIC_PARAMETER_GEN

CKM_DSA_SHAWE_TAYLOR_PARAMETER_GEN

CKM_DSA_FIPS_G_GEN

¨ CK_DSA_PARAMETER_GEN_PARAM

CK_DSA_PARAMETER_GEN_PARAM is a structure which provides and returns parameters for the NIST FIPS 186-4 parameter generating algorithms.

CK_DSA_PARAMETER_GEN_PARAM_PTR is a pointer to a CK_DSA_PARAMETER_GEN_PARAM.

typedef struct CK_DSA_PARAMETER_GEN_PARAM {

CK_MECHANISM_TYPE hash;

CK_BYTE_PTR pSeed;

CK_ULONG ulSeedLen;

CK_ULONG ulIndex;

} CK_DSA_PARAMETER_GEN_PARAM;

The fields of the structure have the following meanings:

hash Mechanism value for the base hash used in PQG generation, Valid values are CKM_SHA_1, CKM_SHA224, CKM_SHA256, CKM_SHA384, CKM_SHA512.

pSeed Seed value used to generate PQ and G. This value is returned by CKM_DSA_PROBABILISTIC_PARAMETER_GEN, CKM_DSA_SHAWE_TAYLOR_PARAMETER_GEN, and passed into CKM_DSA_FIPS_G_GEN.

ulSeedLen Length of seed value.

ulIndex Index value for generating G. Input for CKM_DSA_FIPS_G_GEN. Ignored by CKM_DSA_PROBABILISTIC_PARAMETER_GEN and CKM_DSA_SHAWE_TAYLOR_PARAMETER_GEN.

2.2.2 DSA public key objects

DSA public key objects (object class CKO_PUBLIC_KEY, key type CKK_DSA) hold DSA public keys. The following table defines the DSA public key object attributes, in addition to the common attributes defined for this object class:

Table 19, DSA Public Key Object Attributes

Attribute	Data type	Meaning
CKA_PRIME^1,3	Big integer	Prime p (512 to 3072 bits, in steps of 64 bits)
CKA_SUBPRIME^1,3	Big integer	Subprime q (160, 224 bits, or 256 bits)
CKA_BASE^1,3	Big integer	Base g
CKA_VALUE^1,4	Big integer	Public value y

^{- Refer to [PKCS11-Base]
table 11 for footnotes}

The CKA_PRIME, CKA_SUBPRIME and CKA_BASE attribute values are collectively the “DSA domain parameters”. See FIPS PUB 186-4 for more information on DSA keys.

The following is a sample template for creating a DSA public key object:

CK_OBJECT_CLASS class = CKO_PUBLIC_KEY;

CK_KEY_TYPE keyType = CKK_DSA;

CK_UTF8CHAR label[] = “A DSA public key object”;

CK_BYTE prime[] = {...};

CK_BYTE subprime[] = {...};

CK_BYTE base[] = {...};

CK_BYTE value[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_PRIME, prime, sizeof(prime)},

{CKA_SUBPRIME, subprime, sizeof(subprime)},

{CKA_BASE, base, sizeof(base)},

{CKA_VALUE, value, sizeof(value)}

};

2.2.3 DSA Key Restrictions

FIPS PUB 186-4 specifies permitted combinations of prime and sub-prime lengths. They are:

Prime: 1024 bits, Subprime: 160
Prime: 2048 bits, Subprime: 224
Prime: 2048 bits, Subprime: 256
Prime: 3072 bits, Subprime: 256

Earlier versions of FIPS 186 permitted smaller prime lengths, and those are included here for backwards compatibility. An implementation that is compliant to FIPS 186-4 does not permit the use of primes of any length less than 1024 bits.

2.2.4 DSA private key objects

DSA private key objects (object class CKO_PRIVATE_KEY, key type CKK_DSA) hold DSA private keys. The following table defines the DSA private key object attributes, in addition to the common attributes defined for this object class:

Table 20, DSA Private Key Object Attributes

Attribute	Data type	Meaning
CKA_PRIME^1,4,6	Big integer	Prime p (512 to 1024 bits, in steps of 64 bits)
CKA_SUBPRIME^1,4,6	Big integer	Subprime q (160 bits, 224 bits, or 256 bits)
CKA_BASE^1,4,6	Big integer	Base g
CKA_VALUE^1,4,6,7	Big integer	Private value x

^{- Refer to [PKCS11-Base]
table 11 for footnotes}

The CKA_PRIME, CKA_SUBPRIME and CKA_BASE attribute values are collectively the “DSA domain parameters”. See FIPS PUB 186-4 for more information on DSA keys.

Note that when generating a DSA private key, the DSA domain parameters are not specified in the key’s template. This is because DSA private keys are only generated as part of a DSA key pair, and the DSA domain parameters for the pair are specified in the template for the DSA public key.

The following is a sample template for creating a DSA private key object:

CK_OBJECT_CLASS class = CKO_PRIVATE_KEY;

CK_KEY_TYPE keyType = CKK_DSA;

CK_UTF8CHAR label[] = “A DSA private key object”;

CK_BYTE subject[] = {...};

CK_BYTE id[] = {123};

CK_BYTE prime[] = {...};

CK_BYTE subprime[] = {...};

CK_BYTE base[] = {...};

CK_BYTE value[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_SUBJECT, subject, sizeof(subject)},

{CKA_ID, id, sizeof(id)},

{CKA_SENSITIVE, &true, sizeof(true)},

{CKA_SIGN, &true, sizeof(true)},

{CKA_PRIME, prime, sizeof(prime)},

{CKA_SUBPRIME, subprime, sizeof(subprime)},

{CKA_BASE, base, sizeof(base)},

{CKA_VALUE, value, sizeof(value)}

};

2.2.5 DSA domain parameter objects

DSA domain parameter objects (object class CKO_DOMAIN_PARAMETERS, key type CKK_DSA) hold DSA domain parameters. The following table defines the DSA domain parameter object attributes, in addition to the common attributes defined for this object class:

Table 21, DSA Domain Parameter Object Attributes

Attribute	Data type	Meaning
CKA_PRIME^1,4	Big integer	Prime p (512 to 1024 bits, in steps of 64 bits)
CKA_SUBPRIME^1,4	Big integer	Subprime q (160 bits, 224 bits, or 256 bits)
CKA_BASE^1,4	Big integer	Base g
CKA_PRIME_BITS^2,3	CK_ULONG	Length of the prime value.

^{- Refer to [PKCS11-Base]
table 11 for footnotes}

The CKA_PRIME, CKA_SUBPRIME and CKA_BASE attribute values are collectively the “DSA domain parameters”. See FIPS PUB 186-4 for more information on DSA domain parameters.

To ensure backwards compatibility, if CKA_SUBPRIME_BITS is not specified for a call to C_GenerateKey, it takes on a default based on the value of CKA_PRIME_BITS as follows:

If CKA_PRIME_BITS is less than or equal to 1024 then CKA_SUBPRIME_BITS shall be 160 bits
If CKA_PRIME_BITS equals 2048 then CKA_SUBPRIME_BITS shall be 224 bits
If CKA_PRIME_BITS equals 3072 then CKA_SUBPRIME_BITS shall be 256 bits

The following is a sample template for creating a DSA domain parameter object:

CK_OBJECT_CLASS class = CKO_DOMAIN_PARAMETERS;

CK_KEY_TYPE keyType = CKK_DSA;

CK_UTF8CHAR label[] = “A DSA domain parameter object”;

CK_BYTE prime[] = {...};

CK_BYTE subprime[] = {...};

CK_BYTE base[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_PRIME, prime, sizeof(prime)},

{CKA_SUBPRIME, subprime, sizeof(subprime)},

{CKA_BASE, base, sizeof(base)},

};

2.2.6 DSA key pair generation

The DSA key pair generation mechanism, denoted CKM_DSA_KEY_PAIR_GEN, is a key pair generation mechanism based on the Digital Signature Algorithm defined in FIPS PUB 186-2.

This mechanism does not have a parameter.

The mechanism generates DSA public/private key pairs with a particular prime, subprime and base, as specified in the CKA_PRIME, CKA_SUBPRIME, and CKA_BASE attributes of the template for the public key.

The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, and CKA_VALUE attributes to the new public key and the CKA_CLASS, CKA_KEY_TYPE, CKA_PRIME, CKA_SUBPRIME, CKA_BASE, and CKA_VALUE attributes to the new private key. Other attributes supported by the DSA public and private key types (specifically, the flags indicating which functions the keys support) may also be specified in the templates for the keys, or else are assigned default initial values.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of DSA prime sizes, in bits.

2.2.7 DSA domain parameter generation

The DSA domain parameter generation mechanism, denoted CKM_DSA_PARAMETER_GEN, is a domain parameter generation mechanism based on the Digital Signature Algorithm defined in FIPS PUB 186-2.

This mechanism does not have a parameter.

The mechanism generates DSA domain parameters with a particular prime length in bits, as specified in the CKA_PRIME_BITS attribute of the template.

The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, CKA_PRIME, CKA_SUBPRIME, CKA_BASE and CKA_PRIME_BITS attributes to the new object. Other attributes supported by the DSA domain parameter types may also be specified in the template, or else are assigned default initial values.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of DSA prime sizes, in bits.

2.2.8 DSA probabilistic domain parameter generation

The DSA probabilistic domain parameter generation mechanism, denoted CKM_DSA_PROBABILISTIC_PARAMETER_GEN, is a domain parameter generation mechanism based on the Digital Signature Algorithm defined in FIPS PUB 186-4, section Appendix A.1.1 Generation and Validation of Probable Primes..

This mechanism takes a CK_DSA_PARAMETER_GEN_PARAM which supplies the base hash and returns the seed (pSeed) and the length (ulSeedLen).

The mechanism generates DSA the prime and subprime domain parameters with a particular prime length in bits, as specified in the CKA_PRIME_BITS attribute of the template and the subprime length as specified in the CKA_SUBPRIME_BITS attribute of the template.

The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, CKA_PRIME, CKA_SUBPRIME, CKA_PRIME_BITS, and CKA_SUBPRIME_BITS attributes to the new object. CKA_BASE is not set by this call. Other attributes supported by the DSA domain parameter types may also be specified in the template, or else are assigned default initial values.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of DSA prime sizes, in bits.

2.2.9 DSA Shawe-Taylor domain parameter generation

The DSA Shawe-Taylor domain parameter generation mechanism, denoted CKM_DSA_SHAWE_TAYLOR_PARAMETER_GEN, is a domain parameter generation mechanism based on the Digital Signature Algorithm defined in FIPS PUB 186-4, section Appendix A.1.2 Construction and Validation of Provable Primes p and q.

This mechanism takes a CK_DSA_PARAMETER_GEN_PARAM which supplies the base hash and returns the seed (pSeed) and the length (ulSeedLen).

The mechanism generates DSA the prime and subprime domain parameters with a particular prime length in bits, as specified in the CKA_PRIME_BITS attribute of the template and the subprime length as specified in the CKA_SUBPRIME_BITS attribute of the template.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of DSA prime sizes, in bits.

2.2.10 DSA base domain parameter generation

The DSA base domain parameter generation mechanism, denoted CKM_DSA_FIPS_G_GEN, is a base parameter generation mechanism based on the Digital Signature Algorithm defined in FIPS PUB 186-4, section Appendix A.2 Generation of Generator G.

This mechanism takes a CK_DSA_PARAMETER_GEN_PARAM which supplies the base hash the seed (pSeed) and the length (ulSeedLen) and the index value.

The mechanism generates the DSA base with the domain parameter specified in the CKA_PRIME and CKA_SUBPRIME attributes of the template.

The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, and CKA_BASE attributes to the new object. Other attributes supported by the DSA domain parameter types may also be specified in the template, or else are assigned default initial values.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of DSA prime sizes, in bits.

2.2.11 DSA without hashing

The DSA without hashing mechanism, denoted CKM_DSA, is a mechanism for single-part signatures and verification based on the Digital Signature Algorithm defined in FIPS PUB 186-2. (This mechanism corresponds only to the part of DSA that processes the 20-byte hash value; it does not compute the hash value.)

For the purposes of this mechanism, a DSA signature is a 40-byte string, corresponding to the concatenation of the DSA values r and s, each represented most-significant byte first.

It does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 22, DSA: Key And Data Length

Function	Key type	Input length	Output length
C_Sign¹	DSA private key	20, 28, 32, 48, or 64 bits	2*length of subprime
C_Verify¹	DSA public key	(20, 28, 32, 48, or 64 bits), (2*length of subprime)²	N/A

¹ Single-part operations only.

2 Data length, signature length.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of DSA prime sizes, in bits.

2.2.12 DSA with SHA-1

The DSA with SHA-1 mechanism, denoted CKM_DSA_SHA1, is a mechanism for single- and multiple-part signatures and verification based on the Digital Signature Algorithm defined in FIPS PUB 186-2. This mechanism computes the entire DSA specification, including the hashing with SHA-1.

For the purposes of this mechanism, a DSA signature is a 40-byte string, corresponding to the concatenation of the DSA values r and s, each represented most-significant byte first.

This mechanism does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 23, DSA with SHA-1: Key And Data Length

Function	Key type	Input length	Output length
C_Sign	DSA private key	any	2*subprime length
C_Verify	DSA public key	any, 2*subprime length²	N/A

² Data length, signature length.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of DSA prime sizes, in bits.

2.2.13 FIPS 186-4

When CKM_DSA is operated in FIPS mode, only the following bit lengths of p and q, represented by L and N, SHALL be used:

L = 1024, N = 160

L = 2048, N = 224

L = 2048, N = 256

L = 3072, N = 256

2.2.14 DSA with SHA-224

The DSA with SHA-1 mechanism, denoted CKM_DSA_SHA224, is a mechanism for single- and multiple-part signatures and verification based on the Digital Signature Algorithm defined in FIPS PUB 186-4. This mechanism computes the entire DSA specification, including the hashing with SHA-224.

For the purposes of this mechanism, a DSA signature is a string of length 2*subprime, corresponding to the concatenation of the DSA values r and s, each represented most-significant byte first.

This mechanism does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 24, DSA with SHA-244: Key And Data Length

Function	Key type	Input length	Output length
C_Sign	DSA private key	any	2*subprime length
C_Verify	DSA public key	any, 2*subprime length²	N/A

² Data length, signature length.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of DSA prime sizes, in bits.

2.2.15 DSA with SHA-256

The DSA with SHA-1 mechanism, denoted CKM_DSA_SHA256, is a mechanism for single- and multiple-part signatures and verification based on the Digital Signature Algorithm defined in FIPS PUB 186-4. This mechanism computes the entire DSA specification, including the hashing with SHA-256.

For the purposes of this mechanism, a DSA signature is a string of length 2*subprime, corresponding to the concatenation of the DSA values r and s, each represented most-significant byte first.

This mechanism does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 25, DSA with SHA-256: Key And Data Length

Function	Key type	Input length	Output length
C_Sign	DSA private key	any	2*subprime length
C_Verify	DSA public key	any, 2*subprime length²	N/A

² Data length, signature length.

2.2.16 DSA with SHA-384

The DSA with SHA-1 mechanism, denoted CKM_DSA_SHA384, is a mechanism for single- and multiple-part signatures and verification based on the Digital Signature Algorithm defined in FIPS PUB 186-4. This mechanism computes the entire DSA specification, including the hashing with SHA-384.

For the purposes of this mechanism, a DSA signature is a string of length 2*subprime, corresponding to the concatenation of the DSA values r and s, each represented most-significant byte first.

This mechanism does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 26, DSA with SHA-384: Key And Data Length

Function	Key type	Input length	Output length
C_Sign	DSA private key	any	2*subprime length
C_Verify	DSA public key	any, 2*subprime length²	N/A

² Data length, signature length.

2.2.17 DSA with SHA-512

The DSA with SHA-1 mechanism, denoted CKM_DSA_SHA512, is a mechanism for single- and multiple-part signatures and verification based on the Digital Signature Algorithm defined in FIPS PUB 186-4. This mechanism computes the entire DSA specification, including the hashing with SHA-512.

For the purposes of this mechanism, a DSA signature is a string of length 2*subprime, corresponding to the concatenation of the DSA values r and s, each represented most-significant byte first.

This mechanism does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 27, DSA with SHA-512: Key And Data Length

Function	Key type	Input length	Output length
C_Sign	DSA private key	any	2*subprime length
C_Verify	DSA public key	any, 2*subprime length²	N/A

² Data length, signature length.

2.2.18 DSA with SHA3-224

The DSA with SHA3-224 mechanism, denoted CKM_DSA_SHA3_224, is a mechanism for single- and multiple-part signatures and verification based on the Digital Signature Algorithm defined in FIPS PUB 186-4. This mechanism computes the entire DSA specification, including the hashing with SHA3-224.

For the purposes of this mechanism, a DSA signature is a string of length 2*subprime, corresponding to the concatenation of the DSA values r and s, each represented most-significant byte first.

This mechanism does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 28, DSA with SHA3-224: Key And Data Length

Function	Key type	Input length	Output length
C_Sign	DSA private key	any	2*subprime length
C_Verify	DSA public key	any, 2*subprime length²	N/A

² Data length, signature length.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of DSA prime sizes, in bits.

2.2.19 DSA with SHA3-256

The DSA with SHA3-256 mechanism, denoted CKM_DSA_SHA3_256, is a mechanism for single- and multiple-part signatures and verification based on the Digital Signature Algorithm defined in FIPS PUB 186-4. This mechanism computes the entire DSA specification, including the hashing with SHA3-256.

For the purposes of this mechanism, a DSA signature is a string of length 2*subprime, corresponding to the concatenation of the DSA values r and s, each represented most-significant byte first.

This mechanism does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 29, DSA with SHA3-256: Key And Data Length

Function	Key type	Input length	Output length
C_Sign	DSA private key	any	2*subprime length
C_Verify	DSA public key	any, 2*subprime length²	N/A

² Data length, signature length.

2.2.20 DSA with SHA3-384

The DSA with SHA3-384 mechanism, denoted CKM_DSA_SHA3_384, is a mechanism for single- and multiple-part signatures and verification based on the Digital Signature Algorithm defined in FIPS PUB 186-4. This mechanism computes the entire DSA specification, including the hashing with SHA3-384.

For the purposes of this mechanism, a DSA signature is a string of length 2*subprime, corresponding to the concatenation of the DSA values r and s, each represented most-significant byte first.

This mechanism does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 30, DSA with SHA3-384: Key And Data Length

Function	Key type	Input length	Output length
C_Sign	DSA private key	any	2*subprime length
C_Verify	DSA public key	any, 2*subprime length²	N/A

² Data length, signature length.

2.2.21 DSA with SHA3-512

The DSA with SHA3-512 mechanism, denoted CKM_DSA_SHA3_512, is a mechanism for single- and multiple-part signatures and verification based on the Digital Signature Algorithm defined in FIPS PUB 186-4. This mechanism computes the entire DSA specification, including the hashing with SH3A-512.

For the purposes of this mechanism, a DSA signature is a string of length 2*subprime, corresponding to the concatenation of the DSA values r and s, each represented most-significant byte first.

This mechanism does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 31, DSA with SHA3-512: Key And Data Length

Function	Key type	Input length	Output length
C_Sign	DSA private key	any	2*subprime length
C_Verify	DSA public key	any, 2*subprime length²	N/A

² Data length, signature length.

2.3 Elliptic Curve

The Elliptic Curve (EC) cryptosystem (also related to ECDSA) in this document was originally based on the one described in the ANSI X9.62 and X9.63 standards developed by the ANSI X9F1 working group.

The EC cryptosystem developed by the ANSI X9F1 working group was created at a time when EC curves were always represented in their Weierstrass form. Since that time, new curves represented in Edwards form (RFC 8032) and Montgomery form (RFC 7748) have become more common. To support these new curves, the EC cryptosystem in this document has been extended from the original. Additional key generation mechanisms have been added as well as an additional signature generation mechanism.

Table 32, Elliptic Curve Mechanisms vs. Functions

	Functions
Mechanism	Encrypt & Decrypt	Sign & Verify	SR & VR¹	Digest	Gen. Key/ Key Pair	Wrap & Unwrap	Derive
CKM_EC_KEY_PAIR_GEN					ü
CKM_EC_KEY_PAIR_GEN_W_EXTRA_BITS					ü
CKM_EC_EDWARDS_KEY_PAIR_GEN					ü
CKM_EC_MONTGOMERY_KEY_PAIR_GEN					ü
CKM_ECDSA		ü²
CKM_ECDSA_SHA1		ü
CKM_ECDSA_SHA224		ü
CKM_ECDSA_SHA256		ü
CKM_ECDSA_SHA384		ü
CKM_ECDSA_SHA512		ü
CKM_ECDSA_SHA3_224		ü
CKM_ECDSA_SHA3_256		ü
CKM_ECDSA_SHA3_384		ü
CKM_ECDSA_SHA3_512		ü
CKM_EDDSA		ü
CKM_XEDDSA		ü
CKM_ECDH1_DERIVE							ü
CKM_ECDH1_COFACTOR_DERIVE							ü
CKM_ECMQV_DERIVE							ü
CKM_ECDH_AES_KEY_WRAP						ü

Table 33, Mechanism Information Flags

CKF_EC_F_P	0x00100000UL	True if the mechanism can be used with EC domain parameters over F_p
CKF_EC_F_2M	0x00200000UL	True if the mechanism can be used with EC domain parameters over F_2m
CKF_EC_ECPARAMETERS	0x00400000UL	True if the mechanism can be used with EC domain parameters of the choice ecParameters
CKF_EC_OID	0x00800000UL	True if the mechanism can be used with EC domain parameters of the choice oId
CKF_EC_UNCOMPRESS	0x01000000UL	True if the mechanism can be used with elliptic curve point uncompressed
CKF_EC_COMPRESS	0x02000000UL	True if the mechanism can be used with elliptic curve point compressed
CKF_EC_CURVENAME	0x04000000UL	True of the mechanism can be used with EC domain parameters of the choice curveName

Note: CKF_EC_NAMEDCURVE is deprecated with PKCS#11 3.00. It is replaced by CKF_EC_OID.

In these standards, there are two different varieties of EC defined:

1. EC using a field with an odd prime number of elements (i.e. the finite field F_p).

2. EC using a field of characteristic two (i.e. the finite field F_2m).

An EC key in Cryptoki contains information about which variety of EC it is suited for. It is preferable that a Cryptoki library, which can perform EC mechanisms, be capable of performing operations with the two varieties of EC, however this is not required. The CK_MECHANISM_INFO structure CKF_EC_F_P flag identifies a Cryptoki library supporting EC keys over F_p whereas the CKF_EC_F_2M flag identifies a Cryptoki library supporting EC keys over F_2m. A Cryptoki library that can perform EC mechanisms must set either or both of these flags for each EC mechanism.

In these specifications there are also four representation methods to define the domain parameters for an EC key. Only the ecParameters, the oId and the curveName choices are supported in Cryptoki. The CK_MECHANISM_INFO structure CKF_EC_ECPARAMETERS flag identifies a Cryptoki library supporting the ecParameters choice whereas the CKF_EC_OID flag identifies a Cryptoki library supporting the oId choice, and the CKF_EC_CURVENAME flag identifies a Cryptoki library supporting the curveName choice. A Cryptoki library that can perform EC mechanisms must set the appropriate flag(s) for each EC mechanism.

In these specifications, an EC public key (i.e. EC point Q) or the base point G when the ecParameters choice is used can be represented as an octet string of the uncompressed form or the compressed form. The CK_MECHANISM_INFO structure CKF_EC_UNCOMPRESS flag identifies a Cryptoki library supporting the uncompressed form whereas the CKF_EC_COMPRESS flag identifies a Cryptoki library supporting the compressed form. A Cryptoki library that can perform EC mechanisms must set either or both of these flags for each EC mechanism.

Note that an implementation of a Cryptoki library supporting EC with only one variety, one representation of domain parameters or one form may encounter difficulties achieving interoperability with other implementations.

If an attempt to create, generate, derive or unwrap an EC key of an unsupported curve is made, the attempt should fail with the error code CKR_CURVE_NOT_SUPPORTED. If an attempt to create, generate, derive, or unwrap an EC key with invalid or of an unsupported representation of domain parameters is made, that attempt should fail with the error code CKR_DOMAIN_PARAMS_INVALID. If an attempt to create, generate, derive, or unwrap an EC key of an unsupported form is made, that attempt should fail with the error code CKR_TEMPLATE_INCONSISTENT.

2.3.1 EC Signatures

For the purposes of these mechanisms, an ECDSA signature is an octet string of even length which is at most two times nLen octets, where nLen is the length in octets of the base point order n. The signature octets correspond to the concatenation of the ECDSA values r and s, both represented as an octet string of equal length of at most nLen with the most significant byte first. If r and s have different octet length, the shorter of both must be padded with leading zero octets such that both have the same octet length. Loosely spoken, the first half of the signature is r and the second half is s. For signatures created by a token, the resulting signature is always of length 2nLen. For signatures passed to a token for verification, the signature may have a shorter length but must be composed as specified before.

If the length of the hash value is larger than the bit length of n, only the leftmost bits of the hash up to the length of n will be used. Any truncation is done by the token.

Note: For applications, it is recommended to encode the signature as an octet string of length two times nLen if possible. This ensures that the application works with PKCS#11 modules which have been implemented based on an older version of this document. Older versions required all signatures to have length two times nLen. It may be impossible to encode the signature with the maximum length of two times nLen if the application just gets the integer values of r and s (i.e. without leading zeros), but does not know the base point order n, because r and s can have any value between zero and the base point order n.

An EdDSA signature is an octet string of even length which is two times nLen octets, where nLen is calculated as EdDSA parameter b divided by 8. The signature octets correspond to the concatenation of the EdDSA values R and S as defined in [RFC 8032], both represented as an octet string of equal length of nLen bytes in little endian order.

2.3.2 Definitions

This section defines the key type “CKK_EC” for type CK_KEY_TYPE as used in the CKA_KEY_TYPE attribute of key objects.

Note: CKK_ECDSA is deprecated. It is replaced by CKK_EC.

Mechanisms:

CKM_EC_KEY_PAIR_GEN

CKM_EC_EDWARDS_KEY_PAIR_GEN

CKM_EC_MONTGOMERY_KEY_PAIR_GEN

CKM_ECDSA

CKM_ECDSA_SHA1

CKM_ECDSA_SHA224

CKM_ECDSA_SHA256

CKM_ECDSA_SHA384

CKM_ECDSA_SHA512

CKM_ECDSA_SHA3_224

CKM_ECDSA_SHA3_256

CKM_ECDSA_SHA3_384

CKM_ECDSA_SHA3_512

CKM_EDDSA

CKM_XEDDSA

CKM_ECDH1_DERIVE

CKM_ECDH1_COFACTOR_DERIVE

CKM_ECMQV_DERIVE

CKM_ECDH_AES_KEY_WRAP

CKD_NULL

CKD_SHA1_KDF

CKD_SHA224_KDF

CKD_SHA256_KDF

CKD_SHA384_KDF

CKD_SHA512_KDF

CKD_SHA3_224_KDF

CKD_SHA3_256_KDF

CKD_SHA3_384_KDF

CKD_SHA3_512_KDF

CKD_SHA1_KDF_SP800

CKD_SHA224_KDF_SP800

CKD_SHA256_KDF_SP800

CKD_SHA384_KDF_SP800

CKD_SHA512_KDF_SP800

CKD_SHA3_224_KDF_SP800

CKD_SHA3_256_KDF_SP800

CKD_SHA3_384_KDF_SP800

CKD_SHA3_512_KDF_SP800

CKD_BLAKE2B_160_KDF

CKD_BLAKE2B_256_KDF

CKD_BLAKE2B_384_KDF

CKD_BLAKE2B_512_KDF

2.3.3 ECDSA public key objects

EC (also related to ECDSA) public key objects (object class CKO_PUBLIC_KEY, key type CKK_EC) hold EC public keys. The following table defines the EC public key object attributes, in addition to the common attributes defined for this object class:

Table 34, Elliptic Curve Public Key Object Attributes

Attribute	Data type	Meaning
CKA_EC_PARAMS^1,3	Byte array	DER-encoding of an ANSI X9.62 Parameters value
CKA_EC_POINT^1,4	Byte array	DER-encoding of ANSI X9.62 ECPoint value Q

^{- Refer to [PKCS11-Base]
table 11 for footnotes}

Note: CKA_ECDSA_PARAMS is deprecated. It is replaced by CKA_EC_PARAMS.

The CKA_EC_PARAMS attribute value is known as the “EC domain parameters” and is defined in ANSI X9.62 as a choice of three parameter representation methods with the following syntax:

Parameters ::= CHOICE {

ecParameters ECParameters,

oId CURVES.&id({CurveNames}),

implicitlyCA NULL,

curveName PrintableString

}

The following is a sample template for creating an EC (ECDSA) public key object:

CK_OBJECT_CLASS class = CKO_PUBLIC_KEY;

CK_KEY_TYPE keyType = CKK_EC;

CK_UTF8CHAR label[] = “An EC public key object”;

CK_BYTE ecParams[] = {...};

CK_BYTE ecPoint[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_EC_PARAMS, ecParams, sizeof(ecParams)},

{CKA_EC_POINT, ecPoint, sizeof(ecPoint)}

};

2.3.4 Elliptic curve private key objects

EC (also related to ECDSA) private key objects (object class CKO_PRIVATE_KEY, key type CKK_EC) hold EC private keys. See Section 2.3 for more information about EC. The following table defines the EC private key object attributes, in addition to the common attributes defined for this object class:

Table 35, Elliptic Curve Private Key Object Attributes

Attribute	Data type	Meaning
CKA_EC_PARAMS^1,4,6	Byte array	DER-encoding of an ANSI X9.62 Parameters value
CKA_VALUE^1,4,6,7	Big integer	ANSI X9.62 private value d

^{- Refer to [PKCS11-Base]
table 11 for footnotes}

The CKA_EC_PARAMS attribute value is known as the “EC domain parameters” and is defined in ANSI X9.62 as a choice of three parameter representation methods with the following syntax:

Parameters ::= CHOICE {

ecParameters ECParameters,

oId CURVES.&id({CurveNames}),

implicitlyCA NULL,

curveName PrintableString

}

This allows detailed specification of all required values using choice ecParameters, the use of oId as an object identifier substitute for a particular set of elliptic curve domain parameters, or implicitlyCA to indicate that the domain parameters are explicitly defined elsewhere, or curveName to specify a curve name as e.g. define in [ANSI X9.62], [BRAINPOOL], [SEC 2], [LEGIFRANCE]. The use of oId or curveName is recommended over the choice ecParameters. The choice implicitlyCA must not be used in Cryptoki.Note that when generating an EC private key, the EC domain parameters are not specified in the key’s template. This is because EC private keys are only generated as part of an EC key pair, and the EC domain parameters for the pair are specified in the template for the EC public key.

The following is a sample template for creating an EC (ECDSA) private key object:

CK_OBJECT_CLASS class = CKO_PRIVATE_KEY;

CK_KEY_TYPE keyType = CKK_EC;

CK_UTF8CHAR label[] = “An EC private key object”;

CK_BYTE subject[] = {...};

CK_BYTE id[] = {123};

CK_BYTE ecParams[] = {...};

CK_BYTE value[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_SUBJECT, subject, sizeof(subject)},

{CKA_ID, id, sizeof(id)},

{CKA_SENSITIVE, &true, sizeof(true)},

{CKA_DERIVE, &true, sizeof(true)},

{CKA_EC_PARAMS, ecParams, sizeof(ecParams)},

{CKA_VALUE, value, sizeof(value)}

};

2.3.5 Edwards Elliptic curve public key objects

Edwards EC public key objects (object class CKO_PUBLIC_KEY, key type CKK_EC_EDWARDS) hold Edwards EC public keys. The following table defines the Edwards EC public key object attributes, in addition to the common attributes defined for this object class:

Table 36, Edwards Elliptic Curve Public Key Object Attributes

Attribute	Data type	Meaning
CKA_EC_PARAMS^1,3	Byte array	DER-encoding of a Parameters value as defined above
CKA_EC_POINT^1,4	Byte array	DER-encoding of the b-bit public key value in little endian order as defined in RFC 8032

^{- Refer to [PKCS
#11-Base] table 11 for footnotes}

The CKA_EC_PARAMS attribute value is known as the “EC domain parameters” and is defined in ANSI X9.62 as a choice of three parameter representation methods. A 4^th choice is added to support Edwards and Montgomery Elliptic curves. The CKA_EC_PARAMS attribute has the following syntax:

Parameters ::= CHOICE {

ecParameters ECParameters,

oId CURVES.&id({CurveNames}),

implicitlyCA NULL,

curveName PrintableString

}

Edwards EC public keys only support the use of the curveName selection to specify a curve name as defined in [RFC 8032] and the use of the oID selection to specify a curve through an EdDSA algorithm as defined in [RFC 8410]. Note that keys defined by RFC 8032 and RFC 8410 are incompatible.

The following is a sample template for creating an Edwards EC public key object with Edwards25519 being specified as curveName:

CK_OBJECT_CLASS class = CKO_PUBLIC_KEY;

CK_KEY_TYPE keyType = CKK_EC;

CK_UTF8CHAR label[] = “An Edwards EC public key object”;

CK_BYTE ecParams[] = {0x13, 0x0c, 0x65, 0x64, 0x77, 0x61, 0x72, 0x64, 0x73, 0x32, 0x35, 0x35, 0x31, 0x39};

CK_BYTE ecPoint[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_EC_PARAMS, ecParams, sizeof(ecParams)},

{CKA_EC_POINT, ecPoint, sizeof(ecPoint)}

};

2.3.6 Edwards Elliptic curve private key objects

Edwards EC private key objects (object class CKO_PRIVATE_KEY, key type CKK_EC_EDWARDS) hold Edwards EC private keys. See Section 2.3 for more information about EC. The following table defines the Edwards EC private key object attributes, in addition to the common attributes defined for this object class:

Table 37, Edwards Elliptic Curve Private Key Object Attributes

Attribute	Data type	Meaning
CKA_EC_PARAMS^1,4,6	Byte array	DER-encoding of a Parameters value as defined above
CKA_VALUE^1,4,6,7	Big integer	b-bit private key value in little endian order as defined in RFC 8032

^{- Refer to [PKCS
#11-Base] table 11 for footnotes}

Parameters ::= CHOICE {

ecParameters ECParameters,

oId CURVES.&id({CurveNames}),

implicitlyCA NULL,

curveName PrintableString

}

Edwards EC private keys only support the use of the curveName selection to specify a curve name as defined in [RFC 8032] and the use of the oID selection to specify a curve through an EdDSA algorithm as defined in [RFC 8410]. Note that keys defined by RFC 8032 and RFC 8410 are incompatible.

Note that when generating an Edwards EC private key, the EC domain parameters are not specified in the key’s template. This is because Edwards EC private keys are only generated as part of an Edwards EC key pair, and the EC domain parameters for the pair are specified in the template for the Edwards EC public key.

The following is a sample template for creating an Edwards EC private key object:

CK_OBJECT_CLASS class = CKO_PRIVATE_KEY;

CK_KEY_TYPE keyType = CKK_EC;

CK_UTF8CHAR label[] = “An Edwards EC private key object”;

CK_BYTE subject[] = {...};

CK_BYTE id[] = {123};

CK_BYTE ecParams[] = {...};

CK_BYTE value[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_SUBJECT, subject, sizeof(subject)},

{CKA_ID, id, sizeof(id)},

{CKA_SENSITIVE, &true, sizeof(true)},

{CKA_DERIVE, &true, sizeof(true)},

{CKA_VALUE, value, sizeof(value)}

};

2.3.7 Montgomery Elliptic curve public key objects

Montgomery EC public key objects (object class CKO_PUBLIC_KEY, key type CKK_EC_MONTGOMERY) hold Montgomery EC public keys. The following table defines the Montgomery EC public key object attributes, in addition to the common attributes defined for this object class:

Table 38, Montgomery Elliptic Curve Public Key Object Attributes

Attribute	Data type	Meaning
CKA_EC_PARAMS^1,3	Byte array	DER-encoding of a Parameters value as defined above
CKA_EC_POINT^1,4	Byte array	DER-encoding of the public key value in little endian order as defined in RFC 7748

^{- Refer to [PKCS
#11-Base] table 11 for footnotes}

Parameters ::= CHOICE {

ecParameters ECParameters,

oId CURVES.&id({CurveNames}),

implicitlyCA NULL,

curveName PrintableString

}

Montgomery EC public keys only support the use of the curveName selection to specify a curve name as defined in [RFC7748] and the use of the oID selection to specify a curve through an ECDH algorithm as defined in [RFC 8410]. Note that keys defined by RFC 7748 and RFC 8410 are incompatible.

The following is a sample template for creating a Montgomery EC public key object:

CK_OBJECT_CLASS class = CKO_PUBLIC_KEY;

CK_KEY_TYPE keyType = CKK_EC;

CK_UTF8CHAR label[] = “A Montgomery EC public key object”;

CK_BYTE ecParams[] = {...};

CK_BYTE ecPoint[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_EC_PARAMS, ecParams, sizeof(ecParams)},

{CKA_EC_POINT, ecPoint, sizeof(ecPoint)}

};

2.3.8 Montgomery Elliptic curve private key objects

Montgomery EC private key objects (object class CKO_PRIVATE_KEY, key type CKK_EC_MONTGOMERY) hold Montgomery EC private keys. See Section 2.3 for more information about EC. The following table defines the Montgomery EC private key object attributes, in addition to the common attributes defined for this object class:

Table 39, Montgomery Elliptic Curve Private Key Object Attributes

Attribute	Data type	Meaning
CKA_EC_PARAMS^1,4,6	Byte array	DER-encoding of a Parameters value as defined above
CKA_VALUE^1,4,6,7	Big integer	Private key value in little endian order as defined in RFC 7748

^{- Refer to [PKCS
#11-Base] table 11 for footnotes}

Parameters ::= CHOICE {

ecParameters ECParameters,

oId CURVES.&id({CurveNames}),

implicitlyCA NULL,

curveName PrintableString

}

Edwards EC private keys only support the use of the curveName selection to specify a curve name as defined in [RFC7748] and the use of the oID selection to specify a curve through an ECDH algorithm as defined in [RFC 8410]. Note that keys defined by RFC 7748 and RFC 8410 are incompatible.

Note that when generating a Montgomery EC private key, the EC domain parameters are not specified in the key’s template. This is because Montgomery EC private keys are only generated as part of a Montgomery EC key pair, and the EC domain parameters for the pair are specified in the template for the Montgomery EC public key.

The following is a sample template for creating a Montgomery EC private key object:

CK_OBJECT_CLASS class = CKO_PRIVATE_KEY;

CK_KEY_TYPE keyType = CKK_EC;

CK_UTF8CHAR label[] = “A Montgomery EC private key object”;

CK_BYTE subject[] = {...};

CK_BYTE id[] = {123};

CK_BYTE ecParams[] = {...};

CK_BYTE value[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_SUBJECT, subject, sizeof(subject)},

{CKA_ID, id, sizeof(id)},

{CKA_SENSITIVE, &true, sizeof(true)},

{CKA_DERIVE, &true, sizeof(true)},

{CKA_VALUE, value, sizeof(value)}

};

2.3.9 Elliptic curve key pair generation

The EC (also related to ECDSA) key pair generation mechanism, denoted CKM_EC_KEY_PAIR_GEN, is a key pair generation mechanism that uses the method defined by the ANSI X9.62 and X9.63 standards.

The EC (also related to ECDSA) key pair generation mechanism, denoted CKM_EC_KEY_PAIR_GEN_W_EXTRA_BITS, is a key pair generation mechanism that uses the method defined by FIPS 186-4 Appendix B.4.1.

These mechanisms do not have a parameter.

These mechanisms generate EC public/private key pairs with particular EC domain parameters, as specified in the CKA_EC_PARAMS attribute of the template for the public key. Note that this version of Cryptoki does not include a mechanism for generating these EC domain parameters.

These mechanism contribute the CKA_CLASS, CKA_KEY_TYPE, and CKA_EC_POINT attributes to the new public key and the CKA_CLASS, CKA_KEY_TYPE, CKA_EC_PARAMS and CKA_VALUE attributes to the new private key. Other attributes supported by the EC public and private key types (specifically, the flags indicating which functions the keys support) may also be specified in the templates for the keys, or else are assigned default initial values.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the minimum and maximum supported number of bits in the field sizes, respectively. For example, if a Cryptoki library supports only ECDSA using a field of characteristic 2 which has between 2²⁰⁰ and 2³⁰⁰ elements, then ulMinKeySize = 201 and ulMaxKeySize = 301 (when written in binary notation, the number 2²⁰⁰ consists of a 1 bit followed by 200 0 bits. It is therefore a 201-bit number. Similarly, 2³⁰⁰ is a 301-bit number).

2.3.10 Edwards Elliptic curve key pair generation

The Edwards EC key pair generation mechanism, denoted CKM_EC_EDWARDS_KEY_PAIR_GEN, is a key pair generation mechanism for EC keys over curves represented in Edwards form.

This mechanism does not have a parameter.

The mechanism can only generate EC public/private key pairs over the curves edwards25519 and edwards448 as defined in RFC 8032 or the curves id-Ed25519 and id-Ed448 as defined in RFC 8410. These curves can only be specified in the CKA_EC_PARAMS attribute of the template for the public key using the curveName or the oID methods. Attempts to generate keys over these curves using any other EC key pair generation mechanism will fail with CKR_CURVE_NOT_SUPPORTED.

The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, and CKA_EC_POINT attributes to the new public key and the CKA_CLASS, CKA_KEY_TYPE, CKA_EC_PARAMS and CKA_VALUE attributes to the new private key. Other attributes supported by the Edwards EC public and private key types (specifically, the flags indicating which functions the keys support) may also be specified in the templates for the keys, or else are assigned default initial values.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the minimum and maximum supported number of bits in the field sizes, respectively. For this mechanism, the only allowed values are 255 and 448 as RFC 8032 only defines curves of these two sizes. A Cryptoki implementation may support one or both of these curves and should set the ulMinKeySize and ulMaxKeySize fields accordingly.

2.3.11 Montgomery Elliptic curve key pair generation

The Montgomery EC key pair generation mechanism, denoted CKM_EC_MONTGOMERY_KEY_PAIR_GEN, is a key pair generation mechanism for EC keys over curves represented in Montgomery form.

This mechanism does not have a parameter.

The mechanism can only generate Montgomery EC public/private key pairs over the curves curve25519 and curve448 as defined in RFC 7748 or the curves id-X25519 and id-X448 as defined in RFC 8410. These curves can only be specified in the CKA_EC_PARAMS attribute of the template for the public key using the curveName or oId methods. Attempts to generate keys over these curves using any other EC key pair generation mechanism will fail with CKR_CURVE_NOT_SUPPORTED.

The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, and CKA_EC_POINT attributes to the new public key and the CKA_CLASS, CKA_KEY_TYPE, CKA_EC_PARAMS and CKA_VALUE attributes to the new private key. Other attributes supported by the EC public and private key types (specifically, the flags indicating which functions the keys support) may also be specified in the templates for the keys, or else are assigned default initial values.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the minimum and maximum supported number of bits in the field sizes, respectively. For this mechanism, the only allowed values are 255 and 448 as RFC 7748 only defines curves of these two sizes. A Cryptoki implementation may support one or both of these curves and should set the ulMinKeySize and ulMaxKeySize fields accordingly.

2.3.12 ECDSA without hashing

Refer section 2.3.1 for signature encoding.

The ECDSA without hashing mechanism, denoted CKM_ECDSA, is a mechanism for single-part signatures and verification for ECDSA. (This mechanism corresponds only to the part of ECDSA that processes the hash value, which should not be longer than 1024 bits; it does not compute the hash value.)

This mechanism does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 40, ECDSA without hashing: Key and Data Length

Function	Key type	Input length	Output length
C_Sign¹	ECDSA private key	any³	2nLen
C_Verify¹	ECDSA public key	any³, £2nLen ²	N/A

¹ Single-part operations only.

2 Data length, signature length.

3 Input the entire raw digest. Internally, this will be truncated to the appropriate number of bits.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the minimum and maximum supported number of bits in the field sizes, respectively. For example, if a Cryptoki library supports only ECDSA using a field of characteristic 2 which has between 2²⁰⁰ and 2³⁰⁰ elements (inclusive), then ulMinKeySize = 201 and ulMaxKeySize = 301 (when written in binary notation, the number 2²⁰⁰ consists of a 1 bit followed by 200 0 bits. It is therefore a 201-bit number. Similarly, 2³⁰⁰ is a 301-bit number).

2.3.13 ECDSA with hashing

Refer to section 2.3.1 for signature encoding.

The ECDSA with SHA-1, SHA-224, SHA-384, SHA-512, SHA3-224, SHA3-256, SHA3-384, SHA3-512 mechanism, denoted CKM_ECDSA_[SHA1|SHA224|SHA384|SHA512|SHA3_224|SHA3_256|SHA3_384|SHA3_512] respectively, is a mechanism for single- and multiple-part signatures and verification for ECDSA. This mechanism computes the entire ECDSA specification, including the hashing with SHA-1, SHA-224, SHA-384, SHA-512, SHA3-224, SHA3-256, SHA3-384, SHA3-512 respectively.

This mechanism does not have a parameter.

Constraints on key types and the length of data are summarized in the following table:

Table 41, ECDSA with hashing: Key and Data Length

Function	Key type	Input length	Output length
C_Sign	ECDSA private key	any	2nLen
C_Verify	ECDSA public key	any, £2nLen²	N/A

² Data length, signature length.

2.3.14 EdDSA

The EdDSA mechanism, denoted CKM_EDDSA, is a mechanism for single-part and multipart signatures and verification for EdDSA. This mechanism implements the five EdDSA signature schemes defined in RFC 8032 and RFC 8410.

For curves according to RFC 8032, this mechanism has an optional parameter, a CK_EDDSA_PARAMS structure. The absence or presence of the parameter as well as its content is used to identify which signature scheme is to be used. The following table enumerates the five signature schemes defined in RFC 8032 and all supported permutations of the mechanism parameter and its content.

Table 42, Mapping to RFC 8032 Signature Schemes

Signature Scheme	Mechanism Param	phFlag	Context Data
Ed25519	Not Required	N/A	N/A
Ed25519ctx	Required	False	Optional
Ed25519ph	Required	True	Optional
Ed448	Required	False	Optional
Ed448ph	Required	True	Optional

For curves according to RFC 8410, the mechanism is implicitly given by the curve, which is EdDSA in pure mode.

Constraints on key types and the length of data are summarized in the following table:

Table 43, EdDSA: Key and Data Length

Function	Key type	Input length	Output length
C_Sign	CKK_EC_EDWARDS private key	any	2bLen
C_Verify	CKK_EC_EDWARDS public key	any, £2bLen ²	N/A

2 Data length, signature length.

Note that for EdDSA in pure mode, Ed25519 and Ed448 the data must be processed twice. Therefore, a token might need to cache all the data, especially when used with C_SignUpdate/C_VerifyUpdate. If tokens are unable to do so they can return CKR_TOKEN_RESOURCE_EXCEEDED.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the minimum and maximum supported number of bits in the field sizes, respectively. For this mechanism, the only allowed values are 255 and 448 as RFC 8032and RFC 8410 only define curves of these two sizes. A Cryptoki implementation may support one or both of these curves and should set the ulMinKeySize and ulMaxKeySize fields accordingly.

2.3.15 XEdDSA

The XEdDSA mechanism, denoted CKM_XEDDSA, is a mechanism for single-part signatures and verification for XEdDSA. This mechanism implements the XEdDSA signature scheme defined in [XEDDSA]. CKM_XEDDSA operates on CKK_EC_MONTGOMERY type EC keys, which allows these keys to be used both for signing/verification and for Diffie-Hellman style key-exchanges. This double use is necessary for the Extended Triple Diffie-Hellman where the long-term identity key is used to sign short-term keys and also contributes to the DH key-exchange.

This mechanism has a parameter, a CK_XEDDSA_PARAMS structure.

Table 44, XEdDSA: Key and Data Length

Function	Key type	Input length	Output length
C_Sign¹	CKK_EC_MONTGOMERY private key	any³	2b
C_Verify¹	CKK_EC_MONTGOMERY public key	any³, £2b ²	N/A

2 Data length, signature length.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the minimum and maximum supported number of bits in the field sizes, respectively. For this mechanism, the only allowed values are 255 and 448 as [XEDDSA] only defines curves of these two sizes. A Cryptoki implementation may support one or both of these curves and should set the ulMinKeySize and ulMaxKeySize fields accordingly.

2.3.16 EC mechanism parameters

¨ CK_EDDSA_PARAMS, CK_EDDSA_PARAMS_PTR

CK_EDDSA_PARAMS is a structure that provides the parameters for the CKM_EDDSA signature mechanism. The structure is defined as follows:

typedef struct CK_EDDSA_PARAMS {

CK_BBOOL phFlag;

CK_ULONG ulContextDataLen;

CK_BYTE_PTR pContextData;

} CK_EDDSA_PARAMS;

The fields of the structure have the following meanings:

phFlag a Boolean value which indicates if Prehashed variant of EdDSA should used

ulContextDataLen the length in bytes of the context data where 0 <= ulContextDataLen <= 255.

pContextData context data shared between the signer and verifier

CK_EDDSA_PARAMS_PTR is a pointer to a CK_EDDSA_PARAMS.

¨ CK_XEDDSA_PARAMS, CK_XEDDSA_PARAMS_PTR

CK_XEDDSA_PARAMS is a structure that provides the parameters for the CKM_XEDDSA signature mechanism. The structure is defined as follows:

typedef struct CK_XEDDSA_PARAMS {

CK_XEDDSA_HASH_TYPE hash;

} CK_XEDDSA_PARAMS;

The fields of the structure have the following meanings:

hash a Hash mechanism to be used by the mechanism.

CK_XEDDSA_PARAMS_PTR is a pointer to a CK_XEDDSA_PARAMS.

¨ CK_XEDDSA_HASH_TYPE, CK_XEDDSA_HASH_TYPE_PTR

CK_XEDDSA_HASH_TYPE is used to indicate the hash function used in XEDDSA. It is defined as follows:

typedef CK_ULONG CK_XEDDSA_HASH_TYPE;

The following table lists the defined functions.

Table 45, EC: Key Derivation Functions

Source Identifier

CKM_BLAKE2B_256

CKM_BLAKE2B_512

CKM_SHA3_256

CKM_SHA3_512

CKM_SHA256

CKM_SHA512

CK_XEDDSA_HASH_TYPE_PTR is a pointer to a CK_XEDDSA_HASH_TYPE.

¨ CK_EC_KDF_TYPE, CK_EC_KDF_TYPE_PTR

CK_EC_KDF_TYPE is used to indicate the Key Derivation Function (KDF) applied to derive keying data from a shared secret. The key derivation function will be used by the EC key agreement schemes. It is defined as follows:

typedef CK_ULONG CK_EC_KDF_TYPE;

The following table lists the defined functions.

Table 46, EC: Key Derivation Functions

Source Identifier

CKD_NULL

CKD_SHA1_KDF

CKD_SHA224_KDF

CKD_SHA256_KDF

CKD_SHA384_KDF

CKD_SHA512_KDF

CKD_SHA3_224_KDF

CKD_SHA3_256_KDF

CKD_SHA3_384_KDF

CKD_SHA3_512_KDF

CKD_SHA1_KDF_SP800

CKD_SHA224_KDF_SP800

CKD_SHA256_KDF_SP800

CKD_SHA384_KDF_SP800

CKD_SHA512_KDF_SP800

CKD_SHA3_224_KDF_SP800

CKD_SHA3_256_KDF_SP800

CKD_SHA3_384_KDF_SP800

CKD_SHA3_512_KDF_SP800

CKD_BLAKE2B_160_KDF

CKD_BLAKE2B_256_KDF

CKD_BLAKE2B_384_KDF

CKD_BLAKE2B_512_KDF

The key derivation function CKD_NULL produces a raw shared secret value without applying any key derivation function.

The key derivation functions CKD_[SHA1|SHA224|SHA384|SHA512|SHA3_224|SHA3_256|SHA3_384|SHA3_512]_KDF, which are based on SHA-1, SHA-224, SHA-384, SHA-512, SHA3-224, SHA3-256, SHA3-384, SHA3-512 respectively, derive keying data from the shared secret value as defined in [ANSI X9.63].

The key derivation functions CKD_[SHA1|SHA224|SHA384|SHA512|SHA3_224|SHA3_256|SHA3_384|SHA3_512]_KDF_SP800, which are based on SHA-1, SHA-224, SHA-384, SHA-512, SHA3-224, SHA3-256, SHA3-384, SHA3-512 respectively, derive keying data from the shared secret value as defined in [FIPS SP800-56A] section 5.8.1.1.

The key derivation functions CKD_BLAKE2B_[160|256|384|512]_KDF, which are based on the Blake2b family of hashes, derive keying data from the shared secret value as defined in [FIPS SP800-56A] section 5.8.1.1. CK_EC_KDF_TYPE_PTR is a pointer to a CK_EC_KDF_TYPE.

¨ CK_ECDH1_DERIVE_PARAMS, CK_ECDH1_DERIVE_PARAMS_PTR

CK_ECDH1_DERIVE_PARAMS is a structure that provides the parameters for the CKM_ECDH1_DERIVE and CKM_ECDH1_COFACTOR_DERIVE key derivation mechanisms, where each party contributes one key pair. The structure is defined as follows:

typedef struct CK_ECDH1_DERIVE_PARAMS {

CK_EC_KDF_TYPE kdf;

CK_ULONG ulSharedDataLen;

CK_BYTE_PTR pSharedData;

CK_ULONG ulPublicDataLen;

CK_BYTE_PTR pPublicData;

} CK_ECDH1_DERIVE_PARAMS;

The fields of the structure have the following meanings:

kdf key derivation function used on the shared secret value

ulSharedDataLen the length in bytes of the shared info

pSharedData some data shared between the two parties

ulPublicDataLen the length in bytes of the other party’s EC public key

pPublicData^{^[1]} pointer to other party’s EC public key value. A token MUST be able to accept this value encoded as a raw octet string (as per section A.5.2 of [ANSI X9.62]). A token MAY, in addition, support accepting this value as a DER-encoded ECPoint (as per section E.6 of [ANSI X9.62]) i.e. the same as a CKA_EC_POINT encoding. The calling application is responsible for converting the offered public key to the compressed or uncompressed forms of these encodings if the token does not support the offered form.

With the key derivation function CKD_NULL, pSharedData must be NULL and ulSharedDataLen must be zero. With the key derivation functions CKD_[SHA1|SHA224|SHA384|SHA512|SHA3_224|SHA3_256|SHA3_384|SHA3_512]_KDF, CKD_[SHA1|SHA224|SHA384|SHA512|SHA3_224|SHA3_256|SHA3_384|SHA3_512]_KDF_SP800, an optional pSharedData may be supplied, which consists of some data shared by the two parties intending to share the shared secret. Otherwise, pSharedData must be NULL and ulSharedDataLen must be zero.

CK_ECDH1_DERIVE_PARAMS_PTR is a pointer to a CK_ECDH1_DERIVE_PARAMS.

¨ CK_ECDH2_DERIVE_PARAMS, CK_ECDH2_DERIVE_PARAMS_PTR

CK_ECDH2_DERIVE_PARAMS is a structure that provides the parameters to the CKM_ECMQV_DERIVE key derivation mechanism, where each party contributes two key pairs. The structure is defined as follows:

typedef struct CK_ECDH2_DERIVE_PARAMS {

CK_EC_KDF_TYPE kdf;

CK_ULONG ulSharedDataLen;

CK_BYTE_PTR pSharedData;

CK_ULONG ulPublicDataLen;

CK_BYTE_PTR pPublicData;

CK_ULONG ulPrivateDataLen;

CK_OBJECT_HANDLE hPrivateData;

CK_ULONG ulPublicDataLen2;

CK_BYTE_PTR pPublicData2;

} CK_ECDH2_DERIVE_PARAMS;

The fields of the structure have the following meanings:

kdf key derivation function used on the shared secret value

ulSharedDataLen the length in bytes of the shared info

pSharedData some data shared between the two parties

ulPublicDataLen the length in bytes of the other party’s first EC public key

pPublicData pointer to other party’s first EC public key value. Encoding rules are as per pPublicData of CK_ECDH1_DERIVE_PARAMS

ulPrivateDataLen the length in bytes of the second EC private key

hPrivateData key handle for second EC private key value

ulPublicDataLen2 the length in bytes of the other party’s second EC public key

pPublicData2 pointer to other party’s second EC public key value. Encoding rules are as per pPublicData of CK_ECDH1_DERIVE_PARAMS

With the key derivation function CKD_NULL, pSharedData must be NULL and ulSharedDataLen must be zero. With the key derivation function CKD_SHA1_KDF, an optional pSharedData may be supplied, which consists of some data shared by the two parties intending to share the shared secret. Otherwise, pSharedData must be NULL and ulSharedDataLen must be zero.

CK_ECDH2_DERIVE_PARAMS_PTR is a pointer to a CK_ECDH2_DERIVE_PARAMS.

¨ CK_ECMQV_DERIVE_PARAMS, CK_ECMQV_DERIVE_PARAMS_PTR

CK_ECMQV_DERIVE_PARAMS is a structure that provides the parameters to the CKM_ECMQV_DERIVE key derivation mechanism, where each party contributes two key pairs. The structure is defined as follows:

typedef struct CK_ECMQV_DERIVE_PARAMS {

CK_EC_KDF_TYPE kdf;

CK_ULONG ulSharedDataLen;

CK_BYTE_PTR pSharedData;

CK_ULONG ulPublicDataLen;

CK_BYTE_PTR pPublicData;

CK_ULONG ulPrivateDataLen;

CK_OBJECT_HANDLE hPrivateData;

CK_ULONG ulPublicDataLen2;

CK_BYTE_PTR pPublicData2;

CK_OBJECT_HANDLE publicKey;

} CK_ECMQV_DERIVE_PARAMS;

The fields of the structure have the following meanings:

kdf key derivation function used on the shared secret value

ulSharedDataLen the length in bytes of the shared info

pSharedData some data shared between the two parties

ulPublicDataLen the length in bytes of the other party’s first EC public key

pPublicData pointer to other party’s first EC public key value. Encoding rules are as per pPublicData of CK_ECDH1_DERIVE_PARAMS

ulPrivateDataLen the length in bytes of the second EC private key

hPrivateData key handle for second EC private key value

ulPublicDataLen2 the length in bytes of the other party’s second EC public key

pPublicData2 pointer to other party’s second EC public key value. Encoding rules are as per pPublicData of CK_ECDH1_DERIVE_PARAMS

publicKey Handle to the first party’s ephemeral public key

CK_ECMQV_DERIVE_PARAMS_PTR is a pointer to a CK_ECMQV_DERIVE_PARAMS.

2.3.17 Elliptic curve Diffie-Hellman key derivation

The elliptic curve Diffie-Hellman (ECDH) key derivation mechanism, denoted CKM_ECDH1_DERIVE, is a mechanism for key derivation based on the Diffie-Hellman version of the elliptic curve key agreement scheme, as defined in ANSI X9.63, where each party contributes one key pair all using the same EC domain parameters.

It has a parameter, a CK_ECDH1_DERIVE_PARAMS structure.

This mechanism has the following rules about key sensitivity and extractability:

· The CKA_SENSITIVE and CKA_EXTRACTABLE attributes in the template for the new key can both be specified to be either CK_TRUE or CK_FALSE. If omitted, these attributes each take on some default value.

· If the base key has its CKA_ALWAYS_SENSITIVE attribute set to CK_FALSE, then the derived key will as well. If the base key has its CKA_ALWAYS_SENSITIVE attribute set to CK_TRUE, then the derived key has its CKA_ALWAYS_SENSITIVE attribute set to the same value as its CKA_SENSITIVE attribute.

· Similarly, if the base key has its CKA_NEVER_EXTRACTABLE attribute set to CK_FALSE, then the derived key will, too. If the base key has its CKA_NEVER_EXTRACTABLE attribute set to CK_TRUE, then the derived key has its CKA_NEVER_EXTRACTABLE attribute set to the opposite value from its CKA_EXTRACTABLE attribute.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the minimum and maximum supported number of bits in the field sizes, respectively. For example, if a Cryptoki library supports only EC using a field of characteristic 2 which has between 2²⁰⁰ and 2³⁰⁰ elements, then ulMinKeySize = 201 and ulMaxKeySize = 301 (when written in binary notation, the number 2²⁰⁰ consists of a 1 bit followed by 200 0 bits. It is therefore a 201-bit number. Similarly, 2³⁰⁰ is a 301-bit number).

Constraints on key types are summarized in the following table:

Table 47: ECDH: Allowed Key Types

Function	Key type
C_Derive	CKK_EC or CKK_EC_MONTGOMERY

2.3.18 Elliptic curve Diffie-Hellman with cofactor key derivation

The elliptic curve Diffie-Hellman (ECDH) with cofactor key derivation mechanism, denoted CKM_ECDH1_COFACTOR_DERIVE, is a mechanism for key derivation based on the cofactor Diffie-Hellman version of the elliptic curve key agreement scheme, as defined in ANSI X9.63, where each party contributes one key pair all using the same EC domain parameters. Cofactor multiplication is computationally efficient and helps to prevent security problems like small group attacks.

It has a parameter, a CK_ECDH1_DERIVE_PARAMS structure.

This mechanism has the following rules about key sensitivity and extractability:

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the minimum and maximum supported number of bits in the field sizes, respectively. For example, if a Cryptoki library supports only EC using a field of characteristic 2 which has between 2²⁰⁰ and 2³⁰⁰ elements, then ulMinKeySize = 201 and ulMaxKeySize = 301 (when written in binary notation, the number 2²⁰⁰ consists of a 1 bit followed by 200 0 bits. It is therefore a 201-bit number. Similarly, 2³⁰⁰ is a 301-bit number).

Constraints on key types are summarized in the following table:

Table 48: ECDH with cofactor: Allowed Key Types

Function	Key type
C_Derive	CKK_EC

2.3.19 Elliptic curve Menezes-Qu-Vanstone key derivation

The elliptic curve Menezes-Qu-Vanstone (ECMQV) key derivation mechanism, denoted CKM_ECMQV_DERIVE, is a mechanism for key derivation based the MQV version of the elliptic curve key agreement scheme, as defined in ANSI X9.63, where each party contributes two key pairs all using the same EC domain parameters.

It has a parameter, a CK_ECMQV_DERIVE_PARAMS structure.

This mechanism has the following rules about key sensitivity and extractability:

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the minimum and maximum supported number of bits in the field sizes, respectively. For example, if a Cryptoki library supports only EC using a field of characteristic 2 which has between 2²⁰⁰ and 2³⁰⁰ elements, then ulMinKeySize = 201 and ulMaxKeySize = 301 (when written in binary notation, the number 2²⁰⁰ consists of a 1 bit followed by 200 0 bits. It is therefore a 201-bit number. Similarly, 2³⁰⁰ is a 301-bit number).

Constraints on key types are summarized in the following table:

Table 49: ECDH MQV: Allowed Key Types

Function	Key type
C_Derive	CKK_EC

2.3.20 ECDH AES KEY WRAP

The ECDH AES KEY WRAP mechanism, denoted CKM_ECDH_AES_KEY_WRAP, is a mechanism based on elliptic curve public-key crypto-system and the AES key wrap mechanism. It supports single-part key wrapping; and key unwrapping.

It has a parameter, a CK_ECDH_AES_KEY_WRAP_PARAMS structure.

The mechanism can wrap and unwrap an asymmetric target key of any length and type using an EC key.

- A temporary AES key is derived from a temporary EC key and the wrapping EC key using the CKM_ECDH1_DERIVE mechanism.

- The derived AES key is used for wrapping the target key using the CKM_AES_KEY_WRAP_KWP mechanism.

For wrapping, the mechanism -

Generates a temporary random EC key (transport key) having the same parameters as the wrapping EC key (and domain parameters). Saves the transport key public key material.
Performs ECDH operation using CKM_ECDH1_DERIVE with parameters of kdf, ulSharedDataLen and pSharedData using the private key of the transport EC key and the public key of wrapping EC key and gets the first ulAESKeyBits bits of the derived key to be the temporary AES key.
Wraps the target key with the temporary AES key using CKM_AES_KEY_WRAP_KWP ([AES KEYWRAP] section 6.3).
Zeroizes the temporary AES key and EC transport private key.
Concatenates public key material of the transport key and output the concatenated blob. The first part is the public key material of the transport key and the second part is the wrapped target key.

The recommended format for an asymmetric target key being wrapped is as a PKCS8 PrivateKeyInfo

For unwrapping, the mechanism -

Splits the input into two parts. The first part is the public key material of the transport key and the second part is the wrapped target key. The length of the first part is equal to the length of the public key material of the unwrapping EC key.

Note: since the transport key and the wrapping EC key share the same domain, the length of the public key material of the transport key is the same length of the public key material of the unwrapping EC key.

Performs ECDH operation using CKM_ECDH1_DERIVE with parameters of kdf, ulSharedDataLen and pSharedData using the private part of unwrapping EC key and the public part of the transport EC key and gets first ulAESKeyBits bits of the derived key to be the temporary AES key.
Un-wraps the target key from the second part with the temporary AES key using CKM_AES_KEY_WRAP_KWP ([AES KEYWRAP] section 6.3).
Zeroizes the temporary AES key.

Table 50, CKM_ECDH_AES_KEY_WRAP Mechanisms vs. Functions

	Functions
Mechanism	Encrypt & Decrypt	Sign & Verify	SR & VR1	Digest	Gen. Key/ Key Pair	Wrap & Unwrap	Derive
CKM_ECDH_AES_KEY_WRAP						ü
1SR = SignRecover, VR = VerifyRecover

Constraints on key types are summarized in the following table:

Table 51: ECDH AES Key Wrap: Allowed Key Types

Function	Key type
C_Derive	CKK_EC or CKK_EC_MONTGOMERY

2.3.21 ECDH AES KEY WRAP mechanism parameters

¨ CK_ECDH_AES_KEY_WRAP_PARAMS; CK_ECDH_AES_KEY_WRAP_PARAMS_PTR

CK_ECDH_AES_KEY_WRAP_PARAMS is a structure that provides the parameters to the CKM_ECDH_AES_KEY_WRAP mechanism. It is defined as follows:

typedef struct CK_ECDH_AES_KEY_WRAP_PARAMS {

CK_ULONG ulAESKeyBits;

CK_EC_KDF_TYPE kdf;

CK_ULONG ulSharedDataLen;

CK_BYTE_PTR pSharedData;

} CK_ECDH_AES_KEY_WRAP_PARAMS;

The fields of the structure have the following meanings:

ulAESKeyBits length of the temporary AES key in bits. Can be only 128, 192 or 256.

kdf key derivation function used on the shared secret value to generate AES key.

ulSharedDataLen the length in bytes of the shared info

pSharedData Some data shared between the two parties

CK_ECDH_AES_KEY_WRAP_PARAMS_PTR is a pointer to a CK_ECDH_AES_KEY_WRAP_PARAMS.

2.3.22 FIPS 186-4

When CKM_ECDSA is operated in FIPS mode, the curves SHALL either be NIST recommended curves (with a fixed set of domain parameters) or curves with domain parameters generated as specified by ANSI X9.64. The NIST recommended curves are:

P-192, P-224, P-256, P-384, P-521

K-163, B-163, K-233, B-233

K-283, B-283, K-409, B-409

K-571, B-571

2.4 Diffie-Hellman

Table 52, Diffie-Hellman Mechanisms vs. Functions

	Functions
Mechanism	Encrypt & Decrypt	Sign & Verify	SR & VR¹	Digest	Gen. Key/ Key Pair	Wrap & Unwrap	Derive
CKM_DH_PKCS_KEY_PAIR_GEN					ü
CKM_DH_PKCS_PARAMETER_GEN					ü
CKM_DH_PKCS_DERIVE							ü
CKM_X9_42_DH_KEY_PAIR_GEN					ü
CKM_X9_42_DH_ PARAMETER_GEN					ü
CKM_X9_42_DH_DERIVE							ü
CKM_X9_42_DH_HYBRID_DERIVE							ü
CKM_X9_42_MQV_DERIVE							ü

2.4.1 Definitions

This section defines the key type “CKK_DH” for type CK_KEY_TYPE as used in the CKA_KEY_TYPE attribute of [DH] key objects.

Mechanisms:

CKM_DH_PKCS_KEY_PAIR_GEN

CKM_DH_PKCS_PARAMETER_GEN

CKM_DH_PKCS_DERIVE

CKM_X9_42_DH_KEY_PAIR_GEN

CKM_X9_42_DH_PARAMETER_GEN

CKM_X9_42_DH_DERIVE

CKM_X9_42_DH_HYBRID_DERIVE

CKM_X9_42_MQV_DERIVE

2.4.2 Diffie-Hellman public key objects

Diffie-Hellman public key objects (object class CKO_PUBLIC_KEY, key type CKK_DH) hold Diffie-Hellman public keys. The following table defines the Diffie-Hellman public key object attributes, in addition to the common attributes defined for this object class:

Table 53, Diffie-Hellman Public Key Object Attributes

Attribute	Data type	Meaning
CKA_PRIME^1,3	Big integer	Prime p
CKA_BASE^1,3	Big integer	Base g
CKA_VALUE^1,4	Big integer	Public value y

- Refer to [PKCS11-Base] table 11 for footnotes

The CKA_PRIME and CKA_BASE attribute values are collectively the “Diffie-Hellman domain parameters”. Depending on the token, there may be limits on the length of the key components. See PKCS #3 for more information on Diffie-Hellman keys.

The following is a sample template for creating a Diffie-Hellman public key object:

CK_OBJECT_CLASS class = CKO_PUBLIC_KEY;

CK_KEY_TYPE keyType = CKK_DH;

CK_UTF8CHAR label[] = “A Diffie-Hellman public key object”;

CK_BYTE prime[] = {...};

CK_BYTE base[] = {...};

CK_BYTE value[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_PRIME, prime, sizeof(prime)},

{CKA_BASE, base, sizeof(base)},

{CKA_VALUE, value, sizeof(value)}

};

2.4.3 X9.42 Diffie-Hellman public key objects

X9.42 Diffie-Hellman public key objects (object class CKO_PUBLIC_KEY, key type CKK_X9_42_DH) hold X9.42 Diffie-Hellman public keys. The following table defines the X9.42 Diffie-Hellman public key object attributes, in addition to the common attributes defined for this object class:

Table 54, X9.42 Diffie-Hellman Public Key Object Attributes

Attribute	Data type	Meaning
CKA_PRIME^1,3	Big integer	Prime p (³ 1024 bits, in steps of 256 bits)
CKA_BASE^1,3	Big integer	Base g
CKA_SUBPRIME^1,3	Big integer	Subprime q (³ 160 bits)
CKA_VALUE^1,4	Big integer	Public value y

^{- Refer to [PKCS11-Base]
table 11 for footnotes}

The CKA_PRIME, CKA_BASE and CKA_SUBPRIME attribute values are collectively the “X9.42 Diffie-Hellman domain parameters”. See the ANSI X9.42 standard for more information on X9.42 Diffie-Hellman keys.

The following is a sample template for creating a X9.42 Diffie-Hellman public key object:

CK_OBJECT_CLASS class = CKO_PUBLIC_KEY;

CK_KEY_TYPE keyType = CKK_X9_42_DH;

CK_UTF8CHAR label[] = “A X9.42 Diffie-Hellman public key object”;

CK_BYTE prime[] = {...};

CK_BYTE base[] = {...};

CK_BYTE subprime[] = {...};

CK_BYTE value[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_PRIME, prime, sizeof(prime)},

{CKA_BASE, base, sizeof(base)},

{CKA_SUBPRIME, subprime, sizeof(subprime)},

{CKA_VALUE, value, sizeof(value)}

};

2.4.4 Diffie-Hellman private key objects

Diffie-Hellman private key objects (object class CKO_PRIVATE_KEY, key type CKK_DH) hold Diffie-Hellman private keys. The following table defines the Diffie-Hellman private key object attributes, in addition to the common attributes defined for this object class:

Table 55, Diffie-Hellman Private Key Object Attributes

Attribute	Data type	Meaning
CKA_PRIME^1,4,6	Big integer	Prime p
CKA_BASE^1,4,6	Big integer	Base g
CKA_VALUE^1,4,6,7	Big integer	Private value x
CKA_VALUE_BITS^2,6	CK_ULONG	Length in bits of private value x

^{- Refer to [PKCS11-Base]
table 11 for footnotes}

Note that when generating a Diffie-Hellman private key, the Diffie-Hellman parameters are not specified in the key’s template. This is because Diffie-Hellman private keys are only generated as part of a Diffie-Hellman key pair, and the Diffie-Hellman parameters for the pair are specified in the template for the Diffie-Hellman public key.

The following is a sample template for creating a Diffie-Hellman private key object:

CK_OBJECT_CLASS class = CKO_PRIVATE_KEY;

CK_KEY_TYPE keyType = CKK_DH;

CK_UTF8CHAR label[] = “A Diffie-Hellman private key object”;

CK_BYTE subject[] = {...};

CK_BYTE id[] = {123};

CK_BYTE prime[] = {...};

CK_BYTE base[] = {...};

CK_BYTE value[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_SUBJECT, subject, sizeof(subject)},

{CKA_ID, id, sizeof(id)},

{CKA_SENSITIVE, &true, sizeof(true)},

{CKA_DERIVE, &true, sizeof(true)},

{CKA_PRIME, prime, sizeof(prime)},

{CKA_BASE, base, sizeof(base)},

{CKA_VALUE, value, sizeof(value)}

};

2.4.5 X9.42 Diffie-Hellman private key objects

X9.42 Diffie-Hellman private key objects (object class CKO_PRIVATE_KEY, key type CKK_X9_42_DH) hold X9.42 Diffie-Hellman private keys. The following table defines the X9.42 Diffie-Hellman private key object attributes, in addition to the common attributes defined for this object class:

Table 56, X9.42 Diffie-Hellman Private Key Object Attributes

Attribute	Data type	Meaning
CKA_PRIME^1,4,6	Big integer	Prime p (³ 1024 bits, in steps of 256 bits)
CKA_BASE^1,4,6	Big integer	Base g
CKA_SUBPRIME^1,4,6	Big integer	Subprime q (³ 160 bits)
CKA_VALUE^1,4,6,7	Big integer	Private value x

^{- Refer to [PKCS11-Base]
table 11 for footnotes}

The CKA_PRIME, CKA_BASE and CKA_SUBPRIME attribute values are collectively the “X9.42 Diffie-Hellman domain parameters”. Depending on the token, there may be limits on the length of the key components. See the ANSI X9.42 standard for more information on X9.42 Diffie-Hellman keys.

Note that when generating a X9.42 Diffie-Hellman private key, the X9.42 Diffie-Hellman domain parameters are not specified in the key’s template. This is because X9.42 Diffie-Hellman private keys are only generated as part of a X9.42 Diffie-Hellman key pair, and the X9.42 Diffie-Hellman domain parameters for the pair are specified in the template for the X9.42 Diffie-Hellman public key.

The following is a sample template for creating a X9.42 Diffie-Hellman private key object:

CK_OBJECT_CLASS class = CKO_PRIVATE_KEY;

CK_KEY_TYPE keyType = CKK_X9_42_DH;

CK_UTF8CHAR label[] = “A X9.42 Diffie-Hellman private key object”;

CK_BYTE subject[] = {...};

CK_BYTE id[] = {123};

CK_BYTE prime[] = {...};

CK_BYTE base[] = {...};

CK_BYTE subprime[] = {...};

CK_BYTE value[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_SUBJECT, subject, sizeof(subject)},

{CKA_ID, id, sizeof(id)},

{CKA_SENSITIVE, &true, sizeof(true)},

{CKA_DERIVE, &true, sizeof(true)},

{CKA_PRIME, prime, sizeof(prime)},

{CKA_BASE, base, sizeof(base)},

{CKA_SUBPRIME, subprime, sizeof(subprime)},

{CKA_VALUE, value, sizeof(value)}

};

2.4.6 Diffie-Hellman domain parameter objects

Diffie-Hellman domain parameter objects (object class CKO_DOMAIN_PARAMETERS, key type CKK_DH) hold Diffie-Hellman domain parameters. The following table defines the Diffie-Hellman domain parameter object attributes, in addition to the common attributes defined for this object class:

Table 57, Diffie-Hellman Domain Parameter Object Attributes

Attribute	Data type	Meaning
CKA_PRIME^1,4	Big integer	Prime p
CKA_BASE^1,4	Big integer	Base g
CKA_PRIME_BITS^2,3	CK_ULONG	Length of the prime value.

^{- Refer to [PKCS11-Base]
table 11 for footnotes}

The following is a sample template for creating a Diffie-Hellman domain parameter object:

CK_OBJECT_CLASS class = CKO_DOMAIN_PARAMETERS;

CK_KEY_TYPE keyType = CKK_DH;

CK_UTF8CHAR label[] = “A Diffie-Hellman domain parameters object”;

CK_BYTE prime[] = {...};

CK_BYTE base[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_PRIME, prime, sizeof(prime)},

{CKA_BASE, base, sizeof(base)},

};

2.4.7 X9.42 Diffie-Hellman domain parameters objects

X9.42 Diffie-Hellman domain parameters objects (object class CKO_DOMAIN_PARAMETERS, key type CKK_X9_42_DH) hold X9.42 Diffie-Hellman domain parameters. The following table defines the X9.42 Diffie-Hellman domain parameters object attributes, in addition to the common attributes defined for this object class:

Table 58, X9.42 Diffie-Hellman Domain Parameters Object Attributes

Attribute	Data type	Meaning
CKA_PRIME^1,4	Big integer	Prime p (³ 1024 bits, in steps of 256 bits)
CKA_BASE^1,4	Big integer	Base g
CKA_SUBPRIME^1,4	Big integer	Subprime q (³ 160 bits)
CKA_PRIME_BITS^2,3	CK_ULONG	Length of the prime value.
CKA_SUBPRIME_BITS^2,3	CK_ULONG	Length of the subprime value.

^{- Refer to [PKCS11-Base]
table 11 for footnotes}

The CKA_PRIME, CKA_BASE and CKA_SUBPRIME attribute values are collectively the “X9.42 Diffie-Hellman domain parameters”. Depending on the token, there may be limits on the length of the domain parameters components. See the ANSI X9.42 standard for more information on X9.42 Diffie-Hellman domain parameters.

The following is a sample template for creating a X9.42 Diffie-Hellman domain parameters object:

CK_OBJECT_CLASS class = CKO_DOMAIN_PARAMETERS;

CK_KEY_TYPE keyType = CKK_X9_42_DH;

CK_UTF8CHAR label[] = “A X9.42 Diffie-Hellman domain parameters object”;

CK_BYTE prime[] = {...};

CK_BYTE base[] = {...};

CK_BYTE subprime[] = {...};

CK_BBOOL true = CK_TRUE;

CK_ATTRIBUTE template[] = {

{CKA_CLASS, &class, sizeof(class)},

{CKA_KEY_TYPE, &keyType, sizeof(keyType)},

{CKA_TOKEN, &true, sizeof(true)},

{CKA_LABEL, label, sizeof(label)-1},

{CKA_PRIME, prime, sizeof(prime)},

{CKA_BASE, base, sizeof(base)},

{CKA_SUBPRIME, subprime, sizeof(subprime)},

};

2.4.8 PKCS #3 Diffie-Hellman key pair generation

The PKCS #3 Diffie-Hellman key pair generation mechanism, denoted CKM_DH_PKCS_KEY_PAIR_GEN, is a key pair generation mechanism based on Diffie-Hellman key agreement, as defined in PKCS #3. This is what PKCS #3 calls “phase I”. It does not have a parameter.

The mechanism generates Diffie-Hellman public/private key pairs with a particular prime and base, as specified in the CKA_PRIME and CKA_BASE attributes of the template for the public key. If the CKA_VALUE_BITS attribute of the private key is specified, the mechanism limits the length in bits of the private value, as described in PKCS #3.

The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, and CKA_VALUE attributes to the new public key and the CKA_CLASS, CKA_KEY_TYPE, CKA_PRIME, CKA_BASE, and CKA_VALUE (and the CKA_VALUE_BITS attribute, if it is not already provided in the template) attributes to the new private key; other attributes required by the Diffie-Hellman public and private key types must be specified in the templates.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of Diffie-Hellman prime sizes, in bits.

2.4.9 PKCS #3 Diffie-Hellman domain parameter generation

The PKCS #3 Diffie-Hellman domain parameter generation mechanism, denoted CKM_DH_PKCS_PARAMETER_GEN, is a domain parameter generation mechanism based on Diffie-Hellman key agreement, as defined in PKCS #3.

It does not have a parameter.

The mechanism generates Diffie-Hellman domain parameters with a particular prime length in bits, as specified in the CKA_PRIME_BITS attribute of the template.

The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, CKA_PRIME, CKA_BASE, and CKA_PRIME_BITS attributes to the new object. Other attributes supported by the Diffie-Hellman domain parameter types may also be specified in the template, or else are assigned default initial values.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of Diffie-Hellman prime sizes, in bits.

2.4.10 PKCS #3 Diffie-Hellman key derivation

The PKCS #3 Diffie-Hellman key derivation mechanism, denoted CKM_DH_PKCS_DERIVE, is a mechanism for key derivation based on Diffie-Hellman key agreement, as defined in PKCS #3. This is what PKCS #3 calls “phase II”.

It has a parameter, which is the public value of the other party in the key agreement protocol, represented as a Cryptoki “Big integer” (i.e., a sequence of bytes, most-significant byte first).

This mechanism derives a secret key from a Diffie-Hellman private key and the public value of the other party. It computes a Diffie-Hellman secret value from the public value and private key according to PKCS #3, and truncates the result according to the CKA_KEY_TYPE attribute of the template and, if it has one and the key type supports it, the CKA_VALUE_LEN attribute of the template. (The truncation removes bytes from the leading end of the secret value.) The mechanism contributes the result as the CKA_VALUE attribute of the new key; other attributes required by the key type must be specified in the template.

This mechanism has the following rules about key sensitivity and extractability[2]:

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of Diffie-Hellman prime sizes, in bits.

2.4.11 X9.42 Diffie-Hellman mechanism parameters

¨ CK_X9_42_DH_KDF_TYPE, CK_X9_42_DH_KDF_TYPE_PTR

CK_X9_42_DH_KDF_TYPE is used to indicate the Key Derivation Function (KDF) applied to derive keying data from a shared secret. The key derivation function will be used by the X9.42 Diffie-Hellman key agreement schemes. It is defined as follows:

typedef CK_ULONG CK_X9_42_DH_KDF_TYPE;

The following table lists the defined functions.

Table 59, X9.42 Diffie-Hellman Key Derivation Functions

Source Identifier

CKD_NULL

CKD_SHA1_KDF_ASN1

CKD_SHA1_KDF_CONCATENATE

The key derivation function CKD_NULL produces a raw shared secret value without applying any key derivation function whereas the key derivation functions CKD_SHA1_KDF_ASN1 and CKD_SHA1_KDF_CONCATENATE, which are both based on SHA-1, derive keying data from the shared secret value as defined in the ANSI X9.42 standard.

CK_X9_42_DH_KDF_TYPE_PTR is a pointer to a CK_X9_42_DH_KDF_TYPE.

¨ CK_X9_42_DH1_DERIVE_PARAMS, CK_X9_42_DH1_DERIVE_PARAMS_PTR

CK_X9_42_DH1_DERIVE_PARAMS is a structure that provides the parameters to the CKM_X9_42_DH_DERIVE key derivation mechanism, where each party contributes one key pair. The structure is defined as follows:

typedef struct CK_X9_42_DH1_DERIVE_PARAMS {

CK_X9_42_DH_KDF_TYPE kdf;

CK_ULONG ulOtherInfoLen;

CK_BYTE_PTR pOtherInfo;

CK_ULONG ulPublicDataLen;

CK_BYTE_PTR pPublicData;

} CK_X9_42_DH1_DERIVE_PARAMS;

The fields of the structure have the following meanings:

kdf key derivation function used on the shared secret value

ulOtherInfoLen the length in bytes of the other info

pOtherInfo some data shared between the two parties

ulPublicDataLen the length in bytes of the other party’s X9.42 Diffie-Hellman public key

pPublicData pointer to other party’s X9.42 Diffie-Hellman public key value

With the key derivation function CKD_NULL, pOtherInfo must be NULL and ulOtherInfoLen must be zero. With the key derivation function CKD_SHA1_KDF_ASN1, pOtherInfo must be supplied, which contains an octet string, specified in ASN.1 DER encoding, consisting of mandatory and optional data shared by the two parties intending to share the shared secret. With the key derivation function CKD_SHA1_KDF_CONCATENATE, an optional pOtherInfo may be supplied, which consists of some data shared by the two parties intending to share the shared secret. Otherwise, pOtherInfo must be NULL and ulOtherInfoLen must be zero.

CK_X9_42_DH1_DERIVE_PARAMS_PTR is a pointer to a CK_X9_42_DH1_DERIVE_PARAMS.

· CK_X9_42_DH2_DERIVE_PARAMS, CK_X9_42_DH2_DERIVE_PARAMS_PTR

CK_X9_42_DH2_DERIVE_PARAMS is a structure that provides the parameters to the CKM_X9_42_DH_HYBRID_DERIVE and CKM_X9_42_MQV_DERIVE key derivation mechanisms, where each party contributes two key pairs. The structure is defined as follows:

typedef struct CK_X9_42_DH2_DERIVE_PARAMS {

CK_X9_42_DH_KDF_TYPE kdf;

CK_ULONG ulOtherInfoLen;

CK_BYTE_PTR pOtherInfo;

CK_ULONG ulPublicDataLen;

CK_BYTE_PTR pPublicData;

CK_ULONG ulPrivateDataLen;

CK_OBJECT_HANDLE hPrivateData;

CK_ULONG ulPublicDataLen2;

CK_BYTE_PTR pPublicData2;

} CK_X9_42_DH2_DERIVE_PARAMS;

The fields of the structure have the following meanings:

kdf key derivation function used on the shared secret value

ulOtherInfoLen the length in bytes of the other info

pOtherInfo some data shared between the two parties

ulPublicDataLen the length in bytes of the other party’s first X9.42 Diffie-Hellman public key

pPublicData pointer to other party’s first X9.42 Diffie-Hellman public key value

ulPrivateDataLen the length in bytes of the second X9.42 Diffie-Hellman private key

hPrivateData key handle for second X9.42 Diffie-Hellman private key value

ulPublicDataLen2 the length in bytes of the other party’s second X9.42 Diffie-Hellman public key

pPublicData2 pointer to other party’s second X9.42 Diffie-Hellman public key value

CK_X9_42_DH2_DERIVE_PARAMS_PTR is a pointer to a CK_X9_42_DH2_DERIVE_PARAMS.

· CK_X9_42_MQV_DERIVE_PARAMS, CK_X9_42_MQV_DERIVE_PARAMS_PTR

CK_X9_42_MQV_DERIVE_PARAMS is a structure that provides the parameters to the CKM_X9_42_MQV_DERIVE key derivation mechanism, where each party contributes two key pairs. The structure is defined as follows:

typedef struct CK_X9_42_MQV_DERIVE_PARAMS {

CK_X9_42_DH_KDF_TYPE kdf;

CK_ULONG ulOtherInfoLen;

CK_BYTE_PTR pOtherInfo;

CK_ULONG ulPublicDataLen;

CK_BYTE_PTR pPublicData;

CK_ULONG ulPrivateDataLen;

CK_OBJECT_HANDLE hPrivateData;

CK_ULONG ulPublicDataLen2;

CK_BYTE_PTR pPublicData2;

CK_OBJECT_HANDLE publicKey;

} CK_X9_42_MQV_DERIVE_PARAMS;

The fields of the structure have the following meanings:

kdf key derivation function used on the shared secret value

ulOtherInfoLen the length in bytes of the other info

pOtherInfo some data shared between the two parties

ulPublicDataLen the length in bytes of the other party’s first X9.42 Diffie-Hellman public key

pPublicData pointer to other party’s first X9.42 Diffie-Hellman public key value

ulPrivateDataLen the length in bytes of the second X9.42 Diffie-Hellman private key

hPrivateData key handle for second X9.42 Diffie-Hellman private key value

ulPublicDataLen2 the length in bytes of the other party’s second X9.42 Diffie-Hellman public key

pPublicData2 pointer to other party’s second X9.42 Diffie-Hellman public key value

publicKey Handle to the first party’s ephemeral public key

CK_X9_42_MQV_DERIVE_PARAMS_PTR is a pointer to a CK_X9_42_MQV_DERIVE_PARAMS.

2.4.12 X9.42 Diffie-Hellman key pair generation

The X9.42 Diffie-Hellman key pair generation mechanism, denoted CKM_X9_42_DH_KEY_PAIR_GEN, is a key pair generation mechanism based on Diffie-Hellman key agreement, as defined in the ANSI X9.42 standard.

It does not have a parameter.

The mechanism generates X9.42 Diffie-Hellman public/private key pairs with a particular prime, base and subprime, as specified in the CKA_PRIME, CKA_BASE and CKA_SUBPRIME attributes of the template for the public key.

The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, and CKA_VALUE attributes to the new public key and the CKA_CLASS, CKA_KEY_TYPE, CKA_PRIME, CKA_BASE, CKA_SUBPRIME, and CKA_VALUE attributes to the new private key; other attributes required by the X9.42 Diffie-Hellman public and private key types must be specified in the templates.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of X9.42 Diffie-Hellman prime sizes, in bits, for the CKA_PRIME attribute.

2.4.13 X9.42 Diffie-Hellman domain parameter generation

The X9.42 Diffie-Hellman domain parameter generation mechanism, denoted CKM_X9_42_DH_PARAMETER_GEN, is a domain parameters generation mechanism based on X9.42 Diffie-Hellman key agreement, as defined in the ANSI X9.42 standard.

It does not have a parameter.

The mechanism generates X9.42 Diffie-Hellman domain parameters with particular prime and subprime length in bits, as specified in the CKA_PRIME_BITS and CKA_SUBPRIME_BITS attributes of the template for the domain parameters.

The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, CKA_PRIME, CKA_BASE, CKA_SUBPRIME, CKA_PRIME_BITS and CKA_SUBPRIME_BITS attributes to the new object. Other attributes supported by the X9.42 Diffie-Hellman domain parameter types may also be specified in the template for the domain parameters, or else are assigned default initial values.

For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of X9.42 Diffie-Hellman prime sizes, in bits.

2.4.14 X9.42 Diffie-Hellman key derivation

The X9.42 Diffie-Hellman key derivation mechanism, denoted CKM_X9_42_DH_DERIVE, is a mechanism for key derivation based on the Diffie-Hellman key agreement scheme, as defined in the ANSI X9.42 standard, where each party contributes one key pair, all using the same X9.42 Diffie-Hellman domain parameters.

It has a parameter, a CK_X9_42_DH1_DERIVE_PARAMS structure.

This mechanism derives a secret value, and truncates the result according to the CKA_KEY_TYPE attribute of the template and, if it has one and the key type supports it, the CKA_VALUE_LEN attribute of the template. (The truncation removes bytes from the leading end of the secret value.) The mechanism contributes the result as the CKA_VALUE attribute of the new key; other attributes required by the key type must be specified in the template. Note that in order to validate this mechanism it may be required to use the CKA_VALUE attribute as the key of a general-length MAC mechanism (e.g. CKM_SHA_1_HMAC_GENERAL) over some test data.

This mechanism has the following rules about key sensitivity and extractability:

2.4.15 X9.42 Diffie-Hellman hybrid key derivation

The X9.42 Diffie-Hellman hybrid key derivation mechanism, denoted CKM_X9_42_DH_HYBRID_DERIVE, is a mechanism for key derivation based on the Diffie-Hellman hybrid key agreement scheme, as defined in the ANSI X9.42 standard, where each party contributes two key pair, all using the same X9.42 Diffie-Hellman domain parameters.

It has a parameter, a CK_X9_42_DH2_DERIVE_PARAMS structure.

This mechanism has the following rules about key sensitivity and extractability:

2.4.16 X9.42 Diffie-Hellman Menezes-Qu-Vanstone key derivation

The X9.42 Diffie-Hellman Menezes-Qu-Vanstone (MQV) key derivation mechanism, denoted CKM_X9_42_MQV_DERIVE, is a mechanism for key derivation based the MQV scheme, as defined in the ANSI X9.42 standard, where each party contributes two key pairs, all using the same X9.42 Diffie-Hellman domain parameters.

It has a parameter, a CK_X9_42_MQV_DERIVE_PARAMS structure.

This mechanism has the following rules about key sensitivity and extractability:

2.5 Extended Triple Diffie-Hellman (x3dh)

The Extended Triple Diffie-Hellman mechanism described here is the one described in [SIGNAL].

Table 60, Extended Triple Diffie-Hellman Mechanisms vs. Functions

	Functions
Mechanism	Encrypt & Decrypt	Sign & Verify	SR & VR¹	Digest	Gen.Key/ Key Pair	Wrap & Unwrap	Derive
CKM_X3DH_INITIALIZE							ü
CKM_X3DH_RESPOND							ü

2.5.1 Definitions

Mechanisms:

CKM_X3DH_INITIALIZE

CKM_X3DH_RESPOND

2.5.2 Extended Triple Diffie-Hellman key objects

Extended Triple Diffie-Hellman uses Elliptic Curve keys in Montgomery representation (CKK_EC_MONTGOMERY). Three different kinds of keys are used, they differ in their lifespan:

identity keys are long-term keys, which identify the peer,
prekeys are short-term keys, which should be rotated often (weekly to hourly)
onetime prekeys are keys, which should be used only once.

Any peer intending to be contacted using X3DH must publish their so-called prekey-bundle, consisting of their:

public Identity key,
current prekey, signed using XEDDA with their identity key
optionally a batch of One-time public keys.

2.5.3 Initiating an Extended Triple Diffie-Hellman key exchange

Initiating an Extended Triple Diffie-Hellman key exchange starts by retrieving the following required public keys (the so-called prekey-bundle) of the other peer: the Identity key, the signed public Prekey, and optionally one One-time public key.

When the necessary key material is available, the initiating party calls CKM_X3DH_INITIALIZE, also providing the following additional parameters:

· the initiators identity key

· the initiators ephemeral key (a fresh, one-time CKK_EC_MONTGOMERY type key)

CK_X3DH_INITIATE_PARAMS is a structure that provides the parameters to the CKM_X3DH_INITIALIZE key exchange mechanism. The structure is defined as follows:

typedef struct CK_X3DH_INITIATE_PARAMS {

CK_X3DH_KDF_TYPE kdf;

CK_OBJECT_HANDLE pPeer_identity;

CK_OBJECT_HANDLE pPeer_prekey;

CK_BYTE_PTR pPrekey_signature;

CK_BYTE_PTR pOnetime_key;

CK_OBJECT_HANDLE pOwn_identity;

CK_OBJECT_HANDLE pOwn_ephemeral;

} CK_X3DH_INITIATE_PARAMS;

Table 61, Extended Triple Diffie-Hellman Initiate Message parameters:

Parameter	Data type	Meaning
kdf	CK_X3DH_KDF_TYPE	Key derivation function
pPeer_identity	Key handle	Peers public Identity key (from the prekey-bundle)
pPeer_prekey	Key Handle	Peers public prekey (from the prekey-bundle)
pPrekey_signature	Byte array	XEDDSA signature of PEER_PREKEY (from prekey-bundle)
pOnetime_key	Byte array	Optional one-time public prekey of peer (from the prekey-bundle)
pOwn_identity	Key Handle	Initiators Identity key
pOwn_ephemeral	Key Handle	Initiators ephemeral key

2.5.4 Responding to an Extended Triple Diffie-Hellman key exchange

Responding an Extended Triple Diffie-Hellman key exchange is done by executing a CKM_X3DH_RESPOND mechanism. CK_X3DH_RESPOND_PARAMS is a structure that provides the parameters to the CKM_X3DH_RESPOND key exchange mechanism. All these parameter should be supplied by the Initiator in a message to the responder. The structure is defined as follows:

typedef struct CK_X3DH_RESPOND_PARAMS {

CK_X3DH_KDF_TYPE kdf;

CK_BYTE_PTR pIdentity_id;

CK_BYTE_PTR pPrekey_id;

CK_BYTE_PTR pOnetime_id;

CK_OBJECT_HANDLE pInitiator_identity;

CK_BYTE_PTR pInitiator_ephemeral;

} CK_X3DH_RESPOND_PARAMS;

Table 62, Extended Triple Diffie-Hellman 1st Message parameters:

Parameter	Data type	Meaning
kdf	CK_X3DH_KDF_TYPE	Key derivation function
pIdentity_id	Byte array	Peers public Identity key identifier (from the prekey-bundle)
pPrekey_id	Byte array	Peers public prekey identifier (from the prekey-bundle)
pOnetime_id	Byte array	Optional one-time public prekey of peer (from the prekey-bundle)
pInitiator_identity	Key handle	Initiators Identity key
pInitiator_ephemeral	Byte array	Initiators ephemeral key

Where the *_id fields are identifiers marking which key has been used from the prekey-bundle, these identifiers could be the keys themselves.

This mechanism has the following rules about key sensitivity and extractability[3]:

1 The CKA_SENSITIVE and CKA_EXTRACTABLE attributes in the template for the new key can both be specified to be either CK_TRUE or CK_FALSE. If omitted, these attributes each take on some default value.

2 If the base key has its CKA_ALWAYS_SENSITIVE attribute set to CK_FALSE, then the derived key will as well. If the base key has its CKA_ALWAYS_SENSITIVE attribute set to CK_TRUE, then the derived key has its CKA_ALWAYS_SENSITIVE attribute set to the same value as its CKA_SENSITIVE attribute.

3 Similarly, if the base key has its CKA_NEVER_EXTRACTABLE attribute set to CK_FALSE, then the derived key will, too. If the base key has its CKA_NEVER_EXTRACTABLE attribute set to CK_TRUE, then the derived key has its CKA_NEVER_EXTRACTABLE attribute set to the opposite value from its CKA_EXTRACTABLE attribute.

2.5.5 Extended Triple Diffie-Hellman parameters

· CK_X3DH_KDF_TYPE, CK_X3DH_KDF_TYPE_PTR

CK_X3DH_KDF_TYPE is used to indicate the Key Derivation Function (KDF) applied to derive keying data from a shared secret. The key derivation function will be used by the X3DH key agreement schemes. It is defined as follows:

typedef CK_ULONG CK_X3DH_KDF_TYPE;

The following table lists the defined functions.

Table 63, X3DH: Key Derivation Functions

Source Identifier

CKD_NULL

CKD_BLAKE2B_256_KDF

CKD_BLAKE2B_512_KDF

CKD_SHA3_256_KDF

CKD_SHA256_KDF

CKD_SHA3_512_KDF

CKD_SHA512_KDF

2.6 Double Ratchet

The Double Ratchet is a key management algorithm managing the ongoing renewal and maintenance of short-lived session keys providing forward secrecy and break-in recovery for encrypt/decrypt operations. The algorithm is described in [DoubleRatchet]. The Signal protocol uses X3DH to exchange a shared secret in the first step, which is then used to derive a Double Ratchet secret key.

Table 64, Double Ratchet Mechanisms vs. Functions

	Functions
Mechanism	Encrypt & Decrypt	Sign & Verify	SR & VR1	Digest	Gen. Key/ Key Pair	Wrap & Unwrap	Derive
CKM_X2RATCHET_INITIALIZE							✓
CKM_X2RATCHET_RESPOND							✓
CKM_X2RATCHET_ENCRYPT	✓					✓
CKM_X2RATCHET_DECRYPT	✓					✓

2.6.1 Definitions

This section defines the key type “CKK_X2RATCHET” for type CK_KEY_TYPE as used in the CKA_KEY_TYPE attribute of key objects.

Mechanisms:

CKM_X2RATCHET_INITIALIZE

CKM_X2RATCHET_RESPOND

CKM_X2RATCHET_ENCRYPT

CKM_X2RATCHET_DECRYPT

2.6.2 Double Ratchet secret key objects

Double Ratchet secret key objects (object class CKO_SECRET_KEY, key type CKK_X2RATCHET) hold Double Ratchet keys. Double Ratchet secret keys can only be derived from shared secret keys using the mechanism CKM_X2RATCHET_INITIALIZE or CKM_X2RATCHET_RESPOND. In the Signal protocol these are seeded with the shared secret derived from an Extended Triple Diffie-Hellman [X3DH] key-exchange. The following table defines the Double Ratchet secret key object attributes, in addition to the common attributes defined for this object class:

Table 65, Double Ratchet Secret Key Object Attributes

Attribute	Data type	Meaning
CKA_X2RATCHET_RK	Byte array	Root key
CKA_X2RATCHET_HKS	Byte array	Sender Header key
CKA_X2RATCHET_HKR	Byte array	Receiver Header key
CKA_X2RATCHET_NHKS	Byte array	Next Sender Header Key
CKA_X2RATCHET_NHKR	Byte array	Next Receiver Header Key
CKA_X2RATCHET_CKS	Byte array	Sender Chain key
CKA_X2RATCHET_CKR	Byte array	Receiver Chain key
CKA_X2RATCHET_DHS	Byte array	Sender DH secret key
CKA_X2RATCHET_DHP	Byte array	Sender DH public key
CKA_X2RATCHET_DHR	Byte array	Receiver DH public key
CKA_X2RATCHET_NS	ULONG	Message number send
CKA_X2RATCHET_NR	ULONG	Message number receive
CKA_X2RATCHET_PNS	ULONG	Previous message number send
CKA_X2RATCHET_BOBS1STMSG	BOOL	Is this bob and has he ever sent a message?
CKA_X2RATCHET_ISALICE	BOOL	Is this Alice?
CKA_X2RATCHET_BAGSIZE	ULONG	How many out-of-order keys do we store
CKA_X2RATCHET_BAG	Byte array