LAMPS WG P. Kampanakis
Internet-Draft Cisco Systems
Intended status: Standards Track Q. Dang
Expires: December 31, 2018 NIST
June 29, 2018
Internet X.509 Public Key Infrastructure: Additional Algorithm
Identifiers for RSASSA-PSS and ECDSA using SHAKEs as Hash Functions
draft-ietf-lamps-pkix-shake-02
Abstract
Digital signatures are used to sign messages, X.509 certificates and
CRLs (Certificate Revocation Lists). This document describes the
conventions for using the SHAKE family of hash functions in the
Internet X.509 as one-way hash functions with the RSA Probabilistic
Signature Scheme and ECDSA signature algorithms. The conventions for
the associated subject public keys are also described.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 31, 2018.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
Kampanakis & Dang Expires December 31, 2018 [Page 1]
Internet-Draft SHAKE identifiers in X.509 June 2018
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Identifiers . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Use in PKIX . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. Signatures . . . . . . . . . . . . . . . . . . . . . . . 4
4.1.1. RSASSA-PSS Signatures . . . . . . . . . . . . . . . . 5
4.1.2. ECDSA Signatures . . . . . . . . . . . . . . . . . . 5
4.2. Public Keys . . . . . . . . . . . . . . . . . . . . . . . 6
4.2.1. RSASSA-PSS Public Keys . . . . . . . . . . . . . . . 6
4.2.2. ECDSA Public Keys . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Normative References . . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. ASN.1 module . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Change Log
[ EDNOTE: Remove this section before publication. ]
o draft-ietf-lamps-pkix-shake-02:
* Significant reorganization of the sections to simplify the
introduction, the new OIDs and their use in PKIX.
* Added new OIDs for RSASSA-PSS that hardcode hash, salt and MFG,
according the WG consensus.
* Updated Public Key section to use the new RSASSA-PSS OIDs and
clarify the algorithm identifier usage.
* Removed the no longer used SHAKE OIDs from section 3.1.
* Consolidated subsection for message digest algorithms.
* Text fixes.
o draft-ietf-lamps-pkix-shake-01:
Kampanakis & Dang Expires December 31, 2018 [Page 2]
Internet-Draft SHAKE identifiers in X.509 June 2018
* Changed titles and section names.
* Removed DSA after WG discussions.
* Updated shake OID names and parameters, added MGF1 section.
* Updated RSASSA-PSS section.
* Added Public key algorithm OIDs.
* Populated Introduction and IANA sections.
o draft-ietf-lamps-pkix-shake-00:
* Initial version
2. Introduction
This document describes several cryptographic algorithm identifiers
for several cryptographic algorithms which use variable length output
SHAKE functions introduced in [SHA3] which can be used with the
Internet X.509 Certificate and CRL profile [RFC5280].
The SHA-3 family of one-way hash functions is specified in [SHA3].
In the SHA-3 family, two extendable-output functions, called SHAKE128
and SHAKE256 are defined. Four hash functions, SHA3-224, SHA3-256,
SHA3-384, and SHA3-512 are also defined but are out of scope for this
document. A SHAKE is a variable length hash function. The output
lengths, in bits, of the SHAKE hash functions are defined by the d
parameter. The corresponding collision and preimage resistance
security levels for SHAKE128 and SHAKE256 are respectively
min(d/2,128) and min(d,128) and min(d/2,256) and min(d,256) bits.
SHAKEs can be used as the message digest function (to hash the
message to be signed) and as the hash function in the mask generating
functions in RSASSA-PSS and ECDSA. In this document, we define four
new OIDs for RSASSA-PSS and ECDSA when SHAKE128 and SHAKE256 are used
as hash functions. The same algorithm identifiers are used for
identifying a public key, and identifying a signature.
3. Identifiers
The new identifiers for RSASSA-PSS signatures using SHAKEs are below.
id-RSASSA-PSS-SHAKE128 OBJECT IDENTIFIER ::= { TBD }
Kampanakis & Dang Expires December 31, 2018 [Page 3]
Internet-Draft SHAKE identifiers in X.509 June 2018
id-RSASSA-PSS-SHAKE256 OBJECT IDENTIFIER ::= { TBD }
[ EDNOTE: "TBD" will be specified by NIST later. ]
The new algorithm identifiers of ECDSA signatures using SHAKEs are
below.
id-ecdsa-with-shake128 OBJECT IDENTIFIER ::= { joint-iso-ccitt(2)
country(16) us(840) organization(1) gov(101) csor(3) algorithms(4)
id-ecdsa-with-shake(3) TBD }
id-ecdsa-with-shake256 OBJECT IDENTIFIER ::= { joint-iso-ccitt(2)
country(16) us(840) organization(1) gov(101) csor(3) algorithms(4)
id-ecdsa-with-shake(3) TBD }
[ EDNOTE: "TBD" will be specified by NIST later. ]
The parameters for these four identifiers above MUST be absent. That
is, the identifier SHALL be a SEQUENCE of one component, the OID.
4. Use in PKIX
4.1. Signatures
Signatures can be placed in a number of different ASN.1 structures.
The top level structure for an X.509 certificate, to illustrate how
signatures are frequently encoded with an algorithm identifier and a
location for the signature, is
Certificate ::= SEQUENCE {
tbsCertificate TBSCertificate,
signatureAlgorithm AlgorithmIdentifier,
signatureValue BIT STRING }
The identifiers defined in Section 3 can be used as the
AlgorithmIdentifier in the signatureAlgorithm field in the sequence
Certificate and the signature field in the sequence tbsCertificate in
X.509 [RFC3280].
Conforming CA implementations MUST specify the algorithms explicitly
by using the OIDs specified in Section 3 when encoding RSASSA-PSS and
ECDSA with SHAKE signatures, and public keys in certificates and
CRLs. Encoding rules for RSASSA-PSS and ECDSA signature values are
specified in [RFC4055] and [RFC5480] respectively.
Kampanakis & Dang Expires December 31, 2018 [Page 4]
Internet-Draft SHAKE identifiers in X.509 June 2018
Conforming client implementations that process RSASSA-PSS and ECDSA
with SHAKE signatures when processing certificates and CRLs MUST
recognize the corresponding OIDs.
4.1.1. RSASSA-PSS Signatures
The RSASSA-PSS algorithm is defined in [RFC8017]. When id-RSASSA-
PSS-SHAKE128 or id-RSASSA-PSS-SHAKE256 specified in Section 3 is
used, the encoding MUST omit the parameters field. That is, the
AlgorithmIdentifier SHALL be a SEQUENCE of one component, id-RSASSA-
PSS-SHAKE128 or id-RSASSA-PSS-SHAKE256.
The hash algorithm to hash a message being signed and the hash
algorithm in the maskGenAlgorithm used in RSASSA-PSS MUST be the
same, SHAKE128 or SHAKE256 respectively. The output-length of the
hash algorithm which hashes the message SHALL be 32 or 64 bytes
respectively.
The maskGenAlgorithm is the MGF1 specified in Section B.2.1 of
[RFC8017]. The output length for SHAKE128 or SHAKE256 being used as
the hash function in MGF1 is (n - 264)/8 or (n - 520)/8 bytes
respectively, where n is the RSA modulus in bits. For example, when
RSA modulus n is 2048, the output length of SHAKE128 or SHAKE256 in
the MGF1 will be 223 or 191 when id-RSASSA-PSS-SHAKE128 or id-RSASSA-
PSS-SHAKE256 is used respectively.
The RSASSA-PSS saltLength MUST be 32 or 64 bytes respectively.
Finally, the trailerField MUST be 1, which represents the trailer
field with hexadecimal value 0xBC [RFC8017].
4.1.2. ECDSA Signatures
The Elliptic Curve Digital Signature Algorithm (ECDSA) is defined in
[X9.62]. When the id-ecdsa-with-SHAKE128 or id-ecdsa-with-SHAKE256
(specified in Section 3) algorithm identifier appears, the respective
SHAKE function (SHAKE128 or SHAKE256) is used as the hash. The
encoding MUST omit the parameters field. That is, the
AlgorithmIdentifier SHALL be a SEQUENCE of one component, the OID id-
ecdsa-with-SHAKE128 or id-ecdsa-with-SHAKE256.
For simplicity and compliance with the ECDSA standard specification,
the output size of the hash function must be explicitly determined.
The output size, d, for SHAKE128 or SHAKE256 used in ECDSA MUST be
256 or 512 bits respectively.
Conforming CA implementations that generate ECDSA with SHAKE
signatures in certificates or CRLs MUST generate such signatures in
accordance with all the requirements specified in Sections 7.2 and
Kampanakis & Dang Expires December 31, 2018 [Page 5]
Internet-Draft SHAKE identifiers in X.509 June 2018
7.3 of [X9.62] or with all the requirements specified in
Section 4.1.3 of [SEC1]. They MAY also generate such signatures in
accordance with all the recommendations in [X9.62] or [SEC1] if they
have a stated policy that requires conformance to these standards.
These standards may have not specified SHAKE128 and SHAKE256 as hash
algorithm options. However, SHAKE128 and SHAKE256 with output length
being 32 and 64 octets respectively are subtitutions for 256 and
512-bit output hash algorithms such as SHA256 and SHA512 used in the
standards.
4.2. Public Keys
Certificates conforming to [RFC5280] can convey a public key for any
public key algorithm. The certificate indicates the algorithm
through an algorithm identifier. This algorithm identifier is an OID
and optionally associated parameters.
In the X.509 certificate, the subjectPublicKeyInfo field has the
SubjectPublicKeyInfo type, which has the following ASN.1 syntax:
SubjectPublicKeyInfo ::= SEQUENCE {
algorithm AlgorithmIdentifier,
subjectPublicKey BIT STRING
}
The fields in SubjectPublicKeyInfo have the following meanings:
o algorithm is the algorithm identifier and parameters for the
public key.
o subjectPublicKey contains the byte stream of the public key. The
algorithms defined in this document always encode the public key
as an exact multiple of 8-bits.
The conventions for RSASSA-PSS and ECDSA public keys algorithm
identifiers are as specified in [RFC3279], [RFC4055] and [RFC5480] ,
but we include them below for convenience.
4.2.1. RSASSA-PSS Public Keys
[RFC3279] defines the following OID for RSA AlgorithmIdentifier in
the SubjectPublicKeyInfo with NULL parameters.
rsaEncryption OBJECT IDENTIFIER ::= { pkcs-1 1}
Additionally, when the RSA private key owner wishes to limit the use
of the public key exclusively to RSASSA-PSS, the AlgorithmIdentifiers
for RSASSA-PSS defined in Section 3 can be used as the algorithm
Kampanakis & Dang Expires December 31, 2018 [Page 6]
Internet-Draft SHAKE identifiers in X.509 June 2018
field in the SubjectPublicKeyInfo sequence [RFC3280]. The identifier
parameters, as explained in section Section 3, MUST be absent.
Regardless of what public key algorithm identifier is used, the RSA
public key, which is composed of a modulus and a public exponent,
MUST be encoded using the RSAPublicKey type [RFC4055]. The output of
this encoding is carried in the certificate subjectPublicKey.
RSAPublicKey ::= SEQUENCE {
modulus INTEGER, -- n
publicExponent INTEGER -- e
}
4.2.2. ECDSA Public Keys
For ECDSA, when id-ecdsa-with-shake128 or id-ecdsa-with-shake256 is
used as the AlgorithmIdentifier in the algorithm field of
SubjectPublicKeyInfo, the parameters, as explained in section
Section 3, MUST be absent.
Additionally, the mandatory EC SubjectPublicKey is defined in
Section 2.1.1 and its syntax is in Section 2.2 of [RFC5480]. We also
include them here for convenience:
id-ecPublicKey OBJECT IDENTIFIER ::= {
iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 }
The id-ecPublicKey parameters MUST be present and are defined as
ECParameters ::= CHOICE {
namedCurve OBJECT IDENTIFIER
-- implicitCurve NULL
-- specifiedCurve SpecifiedECDomain
}
The ECParameters associated with the ECDSA public key in the signer's
certificate SHALL apply to the verification of the signature.
5. IANA Considerations
This document uses several new registries [ EDNOTE: Update here. ]
6. Security Considerations
The SHAKEs are deterministic functions. Like any other deterministic
functions, executing each function with the same input multiple times
will produce the same output. Therefore, users should not expect
Kampanakis & Dang Expires December 31, 2018 [Page 7]
Internet-Draft SHAKE identifiers in X.509 June 2018
unrelated outputs (with the same or different output lengths) from
excuting a SHAKE function with the same input multiple times.
Implementations must protect the signer's private key. Compromise of
the signer's private key permits masquerade.
Implementations must randomly generate one-time values, such as the k
value when generating a ECDSA signature. In addition, the generation
of public/private key pairs relies on random numbers. The use of
inadequate pseudo-random number generators (PRNGs) to generate such
cryptographic values can result in little or no security. The
generation of quality random numbers is difficult. [RFC4086] offers
important guidance in this area, and [SP800-90A] series provide
acceptable PRNGs.
Implementers should be aware that cryptographic algorithms may become
weaker with time. As new cryptanalysis techniques are developed and
computing power increases, the work factor or time required to break
a particular cryptographic algorithm may decrease. Therefore,
cryptographic algorithm implementations should be modular allowing
new algorithms to be readily inserted. That is, implementers should
be prepared to regularly update the set of algorithms in their
implementations.
7. Acknowledgements
We would like to thank Sean Turner for his valuable contributions to
this document.
8. References
8.1. Normative References
[RFC3280] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet
X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile", RFC 3280,
DOI 10.17487/RFC3280, April 2002,
.
[RFC4055] Schaad, J., Kaliski, B., and R. Housley, "Additional
Algorithms and Identifiers for RSA Cryptography for use in
the Internet X.509 Public Key Infrastructure Certificate
and Certificate Revocation List (CRL) Profile", RFC 4055,
DOI 10.17487/RFC4055, June 2005,
.
Kampanakis & Dang Expires December 31, 2018 [Page 8]
Internet-Draft SHAKE identifiers in X.509 June 2018
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
.
[RFC5480] Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk,
"Elliptic Curve Cryptography Subject Public Key
Information", RFC 5480, DOI 10.17487/RFC5480, March 2009,
.
[RFC8017] Moriarty, K., Ed., Kaliski, B., Jonsson, J., and A. Rusch,
"PKCS #1: RSA Cryptography Specifications Version 2.2",
RFC 8017, DOI 10.17487/RFC8017, November 2016,
.
[SHA3] National Institute of Standards and Technology, "SHA-3
Standard - Permutation-Based Hash and Extendable-Output
Functions FIPS PUB 202", August 2015,
.
8.2. Informative References
[RFC3279] Bassham, L., Polk, W., and R. Housley, "Algorithms and
Identifiers for the Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 3279, DOI 10.17487/RFC3279, April
2002, .
[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
"Randomness Requirements for Security", BCP 106, RFC 4086,
DOI 10.17487/RFC4086, June 2005,
.
[SEC1] Standards for Efficient Cryptography Group, "SEC 1:
Elliptic Curve Cryptography", May 2009,
.
[SP800-90A]
National Institute of Standards and Technology,
"Recommendation for Random Number Generation Using
Deterministic Random Bit Generators. NIST SP 800-90A",
June 2015,
.
Kampanakis & Dang Expires December 31, 2018 [Page 9]
Internet-Draft SHAKE identifiers in X.509 June 2018
[X9.62] American National Standard for Financial Services (ANSI),
"X9.62-2005 Public Key Cryptography for the Financial
Services Industry: The Elliptic Curve Digital Signature
Standard (ECDSA)", November 2005.
Appendix A. ASN.1 module
[ EDNOTE: More here. ]
Authors' Addresses
Panos Kampanakis
Cisco Systems
Email: pkampana@cisco.com
Quynh Dang
NIST
100 Bureau Drive, Stop 8930
Gaithersburg, MD 20899-8930
USA
Email: quynh.dang@nist.gov
Kampanakis & Dang Expires December 31, 2018 [Page 10]