Network Working Group V. Smyslov
Internet-Draft ELVIS-PLUS
Intended status: Informational August 27, 2020
Expires: February 28, 2021
Using GOST algorithms in IKEv2
draft-smyslov-ike2-gost-04
Abstract
This document defines a set of cryptographic transforms for use in
the Internet Key Exchange version 2 (IKEv2) protocol. The transforms
are based on Russian cryptographic standard algorithms (GOST).
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology and Notation . . . . . . . . . . . . . . . . . . 2
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 2
4. IKE SA Protection . . . . . . . . . . . . . . . . . . . . . . 3
5. Pseudo Random Function . . . . . . . . . . . . . . . . . . . 3
6. Shared Key Calculation . . . . . . . . . . . . . . . . . . . 3
6.1. Recipient Tests . . . . . . . . . . . . . . . . . . . . . 4
7. Authentication . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Hash Functions . . . . . . . . . . . . . . . . . . . . . 4
7.2. ASN.1 Objects . . . . . . . . . . . . . . . . . . . . . . 5
7.2.1. id-tc26-signwithdigest-gost3410-12-256 . . . . . . . 5
7.2.2. id-tc26-signwithdigest-gost3410-12-512 . . . . . . . 5
8. Security Considerations . . . . . . . . . . . . . . . . . . . 5
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
10.1. Normative References . . . . . . . . . . . . . . . . . . 6
10.2. Informative References . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
This document defines a number of transforms for the Internet Key
Exchange version 2 (IKEv2) [RFC7296]. These transforms are based on
Russian cryptographic standard algorithms (often called "GOST"
algorithms) for hash function, digital signature and key exchange
method. Along with transforms defined in [I-D.smyslov-esp-gost], the
transforms defined in this specification allow using GOST
cryptographic algorithms in IPsec protocols.
2. Terminology and Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Overview
Russian cryptographic standard (GOST) algorithms are a set of
cryptographic algorithms of different types - ciphers, hash
functions, digital signatures etc. In particular, Russian
cryptographic standard [GOST3412-2015] defines block ciphers
"Kuznyechik" (also defined in [RFC7801]) and "Magma" (also defined in
[I-D.dolmatov-magma]). Cryptographic standard [GOST3410-2012]
defines elliptic curve digital signature algorithm (also defined in
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[RFC7091]), while [GOST3411-2012] defines two cryptographic hash
functions "Stribog", with different output length (also defined in
[RFC6986]). The parameters for the elliptic curves used in GOST
signature and key exchange algorithms are defined in [RFC7836].
4. IKE SA Protection
Specification [I-D.smyslov-esp-gost] defines two transforms of type 1
(Encryption Algorithm Transform IDs) based on GOST block ciphers that
may be used for IKE SA protection: ENCR_KUZNYECHIK_MGM_KTREE (32)
based on "Kuznyechik" block cipher and ENCR_MAGMA_MGM_KTREE (33)
based on "Magma" block cipher. Since they are AEAD transforms and
provide both encryption and authentication, there is no need for new
transform type 3 (Integrity Algorithm Transform IDs), because it must
not be used with these transforms (or must have a value NONE).
5. Pseudo Random Function
This specification defines a new transform of type 2 (Pseudorandom
Function Transform IDs) - PRF_HMAC_STRIBOG_512 (). This
transform uses PRF HMAC_GOSTR3411_2012_512 defined in Section 4.1.2
of [RFC7836]. The PRF uses GOST R 34.11-2012 ("Stribog") hash-
function with 512-bit output defined in [RFC6986][GOST3411-2012] with
HMAC [RFC2104] construction. The PRF has a 512-bit block size and a
512-bit output length.
6. Shared Key Calculation
This specification defines two new transforms of type 4 (Diffie-
Hellman Group Transform IDs): GOST3410_2012_256 () and
GOST3410_2012_512 (). These transforms uses Elliptic
Curve Diffie-Hellman (ECDH) key exchange algorithm over Twisted
Edwards curves. The parameters for these curves are defined in
Section A.2 of [RFC7836]. In particular, transform GOST3410_2012_256
uses id-tc26-gost-3410-2012-256-paramSetA parameter set and
GOST3410_2012_512 uses id-tc26-gost-3410-2012-512-paramSetC parameter
set (both defined in [RFC7836]).
Shared secret is computed as follows. The initiator randomly selects
its private key d_i from {1,..,q - 1}, where q is the group order and
is a parameter of the selected curve. Then a public key Q_i is
computed as a point on the curve: Q_i = d_i * G, where G is the
generator for the selected curve, and then is sent to the responder.
The responder makes the same calculations to get d_r and Q_r and
sends Q_r to the initiator. After peers exchange Q_i and Q_R both
sides can compute a point on the curve S = ((m / q) * d_i) * Q_r =
((m / q) * d_r) * Q_i, where m is the subgroup order and is a
parameter of the selected curve. The shared secret K is an x
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coordinate of S in a little-endian representation. The size of K is
determined by the size of used curve and is either 256 or 512 bit.
When GOST public key is transmitted in the KE payload, it MUST be
represented as x coordinate immediately followed by y coordinate,
each in a little-endian representation. The size of each coordinate
is determined by the size of the used curve and is either 256 or 512
bits, so that the size of the Key Exchange Data field in the KE
payload is either 64 or 128 octets.
6.1. Recipient Tests
Upon receiving peer's public key implementations MUST check that the
key is actually a point on the curve, otherwise the exchange fails.
Implementations MUST check that the calculated public value S is not
an identity element of the curve, in which case the exchange fails.
7. Authentication
GOST digital signatures algorithm GOST R 34.10-2012 is defined in
[RFC7091][GOST3410-2012]. There are two variants of GOST signature
algorithm - one over 256-bit elliptic curve and the other over
512-bit key elliptic curve.
When GOST digital signature is used in IKEv2 for authentication
purposes, an Authentication Method "Digital Signature" (14) MUST be
specified in the AUTH payload. The AlgorithmIdentifier ASN.1 objects
for GOST digital signature algorithm are defined in Section 7.2.
The signature value, as defined in [RFC7091][GOST3410-2012], consists
of two integers r and s. The size of each integer is either 256 bit
or 512 bit depending on the used elliptic curve. The content of the
Signature Value field in the AUTH payload MUST consist of s
immediately followed by r, each in a big-endian representation, so
that the size of the field is either 64 or 128 octets.
7.1. Hash Functions
GOST digital signatures algorithm uses GOST hash functions GOST R
34.11-2012 ("Stribog") defined in [RFC6986][GOST3411-2012]. There
are two "Stribog" hash functions - one with 256-bit output length and
the other with 512-bit output length.
This specification defines two new values for IKEv2 Hash Algorithms
registry: STRIBOG_256 () for GOST hash function with
256-bit output length and STRIBOG_512 () for the 512-bit
length output. These values MUST be included in the
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SIGNATURE_HASH_ALGORITHMS notify if a corresponding GOST digital
signature algorithm is supported by the sender.
7.2. ASN.1 Objects
This section lists GOST signature algorithm ASN.1 objects in binary
form.
7.2.1. id-tc26-signwithdigest-gost3410-12-256
id-tc26-signwithdigest-gost3410-12-256 OBJECT IDENTIFIER ::= { iso(1)
member-body(2) ru(643) rosstandart(7) tc26(1) algorithms(1)
signwithdigest(3) gost3410-12-256(2) }
Parameters are absent.
Name = id-tc26-signwithdigest-gost3410-12-256
OID = 1.2.643.7.1.1.3.2
Length = 12
0000: 300a 0608 2a85 0307 0101 0302
7.2.2. id-tc26-signwithdigest-gost3410-12-512
id-tc26-signwithdigest-gost3410-12-512 OBJECT IDENTIFIER ::= { iso(1)
member-body(2) ru(643) rosstandart(7) tc26(1) algorithms(1)
signwithdigest(3) gost3410-12-512(3) }
Parameters are absent.
Name = id-tc26-signwithdigest-gost3410-12-256
OID = 1.2.643.7.1.1.3.3
Length = 12
0000: 300a 0608 2a85 0307 0101 0303
8. Security Considerations
The security considerations of [RFC7296] apply accordingly.
The security of GOST elliptic curves is discussed in
[GOST-EC-SECURITY]. The security of "Stribog" hash function is
discussed in [STRIBOG-SECURITY]. A second preimage attack on
"Stribog" is described in [STRIBOG-PREIMAGE] if message size exceeds
2^259 blocks. This attack is not relevant to how "Stribog" is used
in IKEv2.
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9. IANA Considerations
IANA has assigned one Transform ID in the "Transform Type 2 -
Pseudorandom Function Transform IDs" registry (where RFCXXXX is this
document):
Number Name Reference
-------------------------------------------------
9 PRF_HMAC_STRIBOG_512 [RFCXXXX]
IANA has assigned two Transform IDs in the "Transform Type 4 -
Diffie-Hellman Group Transform IDs" registry (where RFCXXXX is this
document):
Number Name Recipient Tests Reference
---------------------------------------------------------------------
33 GOST3410_2012_256 [RFCXXXX] Sec. 6.1 [RFCXXXX]
34 GOST3410_2012_512 [RFCXXXX] Sec. 6.1 [RFCXXXX]
IANA has assigned two values in the "IKEv2 Hash Algorithms" registry
(where RFCXXXX is this document):
Number Hash Algorithm Reference
-------------------------------------------------
6 STRIBOG_256 [RFCXXXX]
7 STRIBOG_512 [RFCXXXX]
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, .
[RFC6986] Dolmatov, V., Ed. and A. Degtyarev, "GOST R 34.11-2012:
Hash Function", RFC 6986, DOI 10.17487/RFC6986, August
2013, .
[RFC7091] Dolmatov, V., Ed. and A. Degtyarev, "GOST R 34.10-2012:
Digital Signature Algorithm", RFC 7091,
DOI 10.17487/RFC7091, December 2013,
.
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[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, .
[RFC7836] Smyshlyaev, S., Ed., Alekseev, E., Oshkin, I., Popov, V.,
Leontiev, S., Podobaev, V., and D. Belyavsky, "Guidelines
on the Cryptographic Algorithms to Accompany the Usage of
Standards GOST R 34.10-2012 and GOST R 34.11-2012",
RFC 7836, DOI 10.17487/RFC7836, March 2016,
.
[I-D.smyslov-esp-gost]
Smyslov, V., "Using GOST ciphers in ESP and IKEv2", draft-
smyslov-esp-gost-03 (work in progress), May 2020.
10.2. Informative References
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104,
DOI 10.17487/RFC2104, February 1997,
.
[RFC7801] Dolmatov, V., Ed., "GOST R 34.12-2015: Block Cipher
"Kuznyechik"", RFC 7801, DOI 10.17487/RFC7801, March 2016,
.
[I-D.dolmatov-magma]
Dolmatov, V. and D. Eremin-Solenikov, "GOST R 34.12-2015:
Block Cipher "Magma"", draft-dolmatov-magma-06 (work in
progress), March 2020.
[GOST3410-2012]
Federal Agency on Technical Regulating and Metrology,
"Information technology. Cryptographic data security.
Signature and verification processes of [electronic]
digital signature", GOST R 34.10-2012, 2012.
(In Russian)
[GOST3411-2012]
Federal Agency on Technical Regulating and Metrology,
"Information technology. Cryptographic data security.
Hashing function", GOST R 34.11-2012, 2012.
(In Russian)
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[GOST3412-2015]
Federal Agency on Technical Regulating and Metrology,
"Information technology. Cryptographic data security.
Block ciphers", GOST R 34.12-2015, 2015.
(In Russian)
[GOST-EC-SECURITY]
Alekseev, E., Nikolaev, V., and S. Smyshlyaev, "On the
security properties of Russian standardized elliptic
curves", https://doi.org/10.4213/mvk260, 2018.
[STRIBOG-SECURITY]
Wang, Z., Yu, H., and X. Wang, "Cryptanalysis of GOST R
hash function",
https://doi.org/10.1016/j.ipl.2014.07.007, 2014.
[STRIBOG-PREIMAGE]
Guo, J., Jean, J., Leurent, G., Peyrin, T., and L. Wang,
"The Usage of Counter Revisited: Second-Preimage Attack on
New Russian Standardized Hash Function",
https://eprint.iacr.org/2014/675, 2014.
Author's Address
Valery Smyslov
ELVIS-PLUS
PO Box 81
Moscow (Zelenograd) 124460
RU
Phone: +7 495 276 0211
Email: svan@elvis.ru
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