Post-Quantum Traditional (PQ/T) Hybrid PKI Authentication in the Internet Key Exchange Version 2 (IKEv2)
draft-hu-ipsecme-pqt-hybrid-auth-01
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Jun Hu , Yasufumi Morioka | ||
| Last updated | 2024-11-03 | ||
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| Intended RFC status | (None) | ||
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draft-hu-ipsecme-pqt-hybrid-auth-01
ipsecme H. Jun
Internet-Draft Nokia
Intended status: Standards Track Y. Morioka
Expires: 7 May 2025 NTT DOCOMO, INC.
3 November 2024
Post-Quantum Traditional (PQ/T) Hybrid PKI Authentication in the
Internet Key Exchange Version 2 (IKEv2)
draft-hu-ipsecme-pqt-hybrid-auth-01
Abstract
One IPsec area that would be impacted by Cryptographically Relevant
Quantum Computer (CRQC) is IKEv2 authentication based on traditional
asymmetric cryptograph algorithms: e.g RSA, ECDSA; which are widely
deployed authentication options of IKEv2. There are new Post-Quantum
Cryptograph (PQC) algorithms for digital signature like NIST
[ML-DSA], however it takes time for new cryptograph algorithms to
mature, so there is security risk to use only the new algorithm
before it is field proven. This document describes a IKEv2 hybrid
authentication scheme that could contain both traditional and PQC
algorithms, so that authentication is secure as long as one algorithm
in the hybrid scheme is secure.
About This Document
This note is to be removed before publishing as an RFC.
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https://example.com/LATEST. Status information for this document may
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hybrid-auth/.
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Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Table of Contents
1. Changes in -01 . . . . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Conventions and Definitions . . . . . . . . . . . . . . . . . 4
4. IKEv2 Key Exchange . . . . . . . . . . . . . . . . . . . . . 4
5. Exchanges . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5.1. Announcement . . . . . . . . . . . . . . . . . . . . . . 5
5.1.1. Sending Announcement . . . . . . . . . . . . . . . . 6
5.1.2. Receiving Announcement . . . . . . . . . . . . . . . 7
5.2. AUTH & CERT payload . . . . . . . . . . . . . . . . . . . 7
5.2.1. Type-1 . . . . . . . . . . . . . . . . . . . . . . . 8
5.2.2. Type-2 . . . . . . . . . . . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . 11
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
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1. Changes in -01
* Only use SUPPORTED_AUTH_METHODS for algorithm combination
announcement, no longer use SIGNATURE_HASH_ALGORITHMS
* add flag field in the announcement
* clarify two types of PKI setup
* add some clarifications on how AUTH payload is computed
2. Introduction
A Cryptographically Relevant Quantum Computer (CRQC) could break
traditional asymmetric cryptograph algorithms: e.g RSA, ECDSA; which
are widely deployed authentication options of IKEv2. New Post-
Quantum Cryptograph (PQC) algorithms for digital signature were
recently published like NIST [ML-DSA], however consider potential
flaws in the new algorithm's specifications and implementations, it
will take time for these new PQC algorithms to be field proven. So
it is risky to only use PQC algorithms before they are mature. There
is more detailed discussion on motivation of a hybrid approach for
authentication in Section 1.3 of
[I-D.ietf-pquip-hybrid-signature-spectrums].
This document describes an IKEv2 hybrid authentication scheme that
contains both traditional and PQC algorithms, so that authentication
is secure as long as one algorithm in the hybrid scheme is secure.
Each IPsec peer announce the support of hybrid authentication via
SUPPORTED_AUTH_METHODS notification as defined in [RFC9593],
generates and verifies AUTH payload using composite signature like
the procedures defined in [I-D.ietf-lamps-pq-composite-sigs].
Following two types of setup are covered:
1. Type-1: A single certificate that has composite key as defined in
[I-D.ietf-lamps-pq-composite-sigs]
2. Type-2: Two certificates, one with traditional algorithm key and
one with PQC algorithm key
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3. Conventions and Definitions
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.
Cryptographically Relevant Quantum Computer (CRQC): A quantum
computer that is capable of breaking real world cryptographic
systems.
Post-Quantum Cryptograph (PQC) algorithms: Asymmetric cryptograph
algorithms are thought to be secure against CRQC.
Traditional Cryptograph algorithms: Existing asymmetric cryptograph
algorithms could be broken by CRQC, like RSA, ECDSA ..etc.
4. IKEv2 Key Exchange
There is no changes introduced in this document to the IKEv2 key
exchange process, although it MUST be also resilient to CRQC when
using along with the PQ/T hybrid authentication, for example key
exchange using the PPK as defined in [RFC8784], or hybrid key
exchanges that include PQC algorithm via multiple key exchange
process as defined in [RFC9370].
5. Exchanges
The hybrid authentication exchanges is illustrated in an example
depicted in Figure 1, the key exchange uses PPK, however it could be
other key exchanges that involves PQC algorithm since how key
exchange is done is transparent to authentication.
Initiator Responder
-------------------------------------------------------------------
HDR, SAi1, KEi, Ni,
N(USE_PPK) -->
<-- HDR, SAr1, KEr, Nr, [CERTREQ,] N(USE_PPK),
N(SUPPORTED_AUTH_METHODS)
HDR, SK {IDi, CERT+, [CERTREQ,]
[IDr,] AUTH, SAi2,
TSi, TSr, N(PPK_IDENTITY, PPK_ID),
N(SUPPORTED_AUTH_METHODS)} -->
<-- HDR, SK {IDr, CERT+, [CERTREQ,]
AUTH, [N(PPK_IDENTITY)]}
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Figure 1: Hybrid Authentication Exchanges with RFC8784 Key Exchange
5.1. Announcement
Announcement of support hybrid authentication is through
SUPPORTED_AUTH_METHODS notification as defined in [RFC9593], which
includes a list of acceptable authentication methods announcements,
this document defines a hybrid authentication announcements with
following format:
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length (>=2) | Auth Method | Cert Link 1 | Alg 1 flag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Alg 1 Len | |
+-+-+-+-+-+-+-+-+ |
~ AlgorithmIdentifier 1 ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cert Link 2 | Alg 2 flag | Alg 2 Len | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
~ AlgorithmIdentifier 2 ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cert Link 3 | Alg 3 flag | Alg 3 Len | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
~ AlgorithmIdentifier N ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Hybrid Authentication Announcement
The announcement include a list of N algorithms could be used for
hybrid signature
* Auth Method: A new value to be allocated by IANA
* Cert Link N: Links corresponding signature algorithm N with a
particular CA. as defined in Section 3.2.2 of [RFC9593]
* Alg N Flag:
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- C: set to 1 if the algorithm could be used in type-1 setup
- S: set to 1 if the algorithm could be used in type-2 setup
- C and S MUST NOT be zero at the same time
- RESERVED: set to 0
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|C|S| RESERVED |
+-+-+-+-+-+-+-+-+
Figure 3: Algorithm Flag
* AlgorithmIdentifier N: The variable-length ASN.1 object that is
encoded using Distinguished Encoding Rules (DER) [X.690] and
identifies the algorithm of a composite signature as defined in
Section 7 of [I-D.ietf-lamps-pq-composite-sigs].
5.1.1. Sending Announcement
As defined in [RFC9593], responder include SUPPORTED_AUTH_METHODS in
IKE_SA_INIT response (and potentially also in IKE_INTERMEDIATE
response), while initiator include the notification in IKE_AUTH
request.
Sender include a hybrid authentication announcement in
SUPPORTED_AUTH_METHODS, which contains 0 or N composite signature
AlgorithmIdentifiers sender accepts, each AlgorithmIdentifier
identifies a combination of algorithms:
* a traditional PKI algorithm with corresponding hash algorithm
(e.g. id-RSASA-PSS with id-sha256)
* a PQC algorithm (e.g. id-ML-DSA-44)
- in case of Hash ML-DSA, there is also a pre-hash algorithm
(e.g. id-sha256)
In case of type-2 setup, even though the certificate is not composite
key certificate, system still uses a composite signature algorithm
that corresponds to the combination of two certificates PKI
algorithms and hash algorithm(s).
C and S bits in flag field are set according to whether sender accept
the algorithm combination in type-1/type-2 setup.
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Announcement without any AlgorithmIdentifiers signals that there is
no particular restrictions on algorithm.
5.1.2. Receiving Announcement
If hybrid authentication announcement is received, and receiver
choose to authenticate itself using hybrid authentication, then based
on its local policy and certificates, one AlgorithmIdentifier (which
identify a combination of algorithms) in the hybrid authentication
announcement and a PKI setup (type-1 or type-2) are chosen to create
its AUTH and CERT payload(s).
5.2. AUTH & CERT payload
The IKEv2 AUTH payload has following format as defined in Section 3.8
of [RFC7296]:
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Payload |C| RESERVED | Payload Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Auth Method | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Authentication Data ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: AUTH payload
For hybrid authentication, the AUTH Method has value defined in
Section 5.1
The Authentication Data field follows format defined in Section 3 of
[RFC7427]:
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1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASN.1 Length | AlgorithmIdentifier ASN.1 object |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ AlgorithmIdentifier ASN.1 object continuing ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Signature Value ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Authentication Data in hybrid AUTH payload
Based on selected AlgorithmIdentifier and setup type, the Signature
Value is created via procedure defined in Section 5.2.1,
Section 5.2.2.
5.2.1. Type-1
Assume selected AlgorithmIdentifier is A.
1. There is no change on data to be signed, e.g.
InitiatorSignedOctets/ResponderSignedOctets as defined in
Section 2.15 of [RFC7296]
2. Follow Sign operation identified by A, e.g. Section 4.2.1 of
[I-D.ietf-lamps-pq-composite-sigs] or Section 4.3.1 of
[I-D.ietf-lamps-pq-composite-sigs]; the ctx input is the string
of "IKEv2-PQT-Hybrid-Auth".
Following is an initiator example:
1. A is id-HashMLDSA44-RSA2048-PSS-SHA256, which uses Hash ML-DSA-44
2. Follow Section 4.3.1 of [I-D.ietf-lamps-pq-composite-sigs] with
following input:
* sk is the private key of the signing composite key certificate
* M is InitiatorSignedOctets
* ctx is "IKEv2-PQT-Hybrid-Auth"
* PH is SHA256
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The signing composite certificate MUST be the first CERT payload.
5.2.2. Type-2
The procedure is same as Type-1, use private key of traditional and
PQC certificate accordingly; e.g. in Sign procedure define in
Section 4.2.1 of [I-D.ietf-lamps-pq-composite-sigs], the mldsaSK is
the private key of ML-DSA certificate, while tradSK is the private
key of traditional certificate.
With the example in Section 5.2.1:
* mldsaSK is the private key of ML-DSA certificate, tradSK is the
private key of the RSA certificate
* M is InitiatorSignedOctets
* ctx is "IKEv2-PQT-Hybrid-Auth"
* PH is SHA256
The signing PQC certificate MUST be the first CERT payload in the
IKEv2 message, while traditional certificate MUST be the second CERT
payload.
5.2.2.1. RelatedCertificate
In type-2 setup, the signing certificate MAY contain
RelatedCertificate extension, then the receiver SHOULD verify the
extension according to Section 4.2 of
[I-D.ietf-lamps-cert-binding-for-multi-auth], failed verification
SHOULD fail authentication.
6. Security Considerations
The security of general PQ/T hybrid authentication is discussed in
[I-D.ietf-pquip-hybrid-signature-spectrums].
This document uses mechanisms defined in
[I-D.ietf-lamps-pq-composite-sigs], [RFC7427] and [RFC9593], the
security discussion in the corresponding RFCs also apply.
7. IANA Considerations
This document requests a value in "IKEv2 Authentication Method"
subregistry under IANA "Internet Key Exchange Version 2 (IKEv2)
Parameters" registry
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8. References
8.1. Normative References
[I-D.ietf-lamps-cert-binding-for-multi-auth]
Becker, A., Guthrie, R., and M. J. Jenkins, "Related
Certificates for Use in Multiple Authentications within a
Protocol", Work in Progress, Internet-Draft, draft-ietf-
lamps-cert-binding-for-multi-auth-05, 29 April 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-lamps-
cert-binding-for-multi-auth-05>.
[I-D.ietf-lamps-pq-composite-sigs]
Ounsworth, M., Gray, J., Pala, M., Klaußner, J., and S.
Fluhrer, "Composite ML-DSA For use in X.509 Public Key
Infrastructure and CMS", Work in Progress, Internet-Draft,
draft-ietf-lamps-pq-composite-sigs-03, 21 October 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-lamps-
pq-composite-sigs-03>.
[I-D.ietf-pquip-hybrid-signature-spectrums]
Bindel, N., Hale, B., Connolly, D., and F. D, "Hybrid
signature spectrums", Work in Progress, Internet-Draft,
draft-ietf-pquip-hybrid-signature-spectrums-00, 24 May
2024, <https://datatracker.ietf.org/doc/html/draft-ietf-
pquip-hybrid-signature-spectrums-00>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[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, <https://www.rfc-editor.org/rfc/rfc7296>.
[RFC7427] Kivinen, T. and J. Snyder, "Signature Authentication in
the Internet Key Exchange Version 2 (IKEv2)", RFC 7427,
DOI 10.17487/RFC7427, January 2015,
<https://www.rfc-editor.org/rfc/rfc7427>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
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[RFC9593] Smyslov, V., "Announcing Supported Authentication Methods
in the Internet Key Exchange Protocol Version 2 (IKEv2)",
RFC 9593, DOI 10.17487/RFC9593, July 2024,
<https://www.rfc-editor.org/rfc/rfc9593>.
[X.690] "Information Technology - ASN.1 encoding rules:
Specification of Basic Encoding Rules (BER), Canonical
Encoding Rules (CER) and Distinguished Encoding Rules
(DER)", ISO/IEC 8825-1:2021 (E), ITU-T Recommendation
X.690, February 2021.
8.2. Informative References
[ML-DSA] "Module-Lattice-Based Digital Signature Standard", NIST
FIPS-204, State Initial Public Draft, August 2023,
<https://csrc.nist.gov/pubs/fips/204/ipd>.
[RFC8784] Fluhrer, S., Kampanakis, P., McGrew, D., and V. Smyslov,
"Mixing Preshared Keys in the Internet Key Exchange
Protocol Version 2 (IKEv2) for Post-quantum Security",
RFC 8784, DOI 10.17487/RFC8784, June 2020,
<https://www.rfc-editor.org/rfc/rfc8784>.
[RFC9370] Tjhai, CJ., Tomlinson, M., Bartlett, G., Fluhrer, S., Van
Geest, D., Garcia-Morchon, O., and V. Smyslov, "Multiple
Key Exchanges in the Internet Key Exchange Protocol
Version 2 (IKEv2)", RFC 9370, DOI 10.17487/RFC9370, May
2023, <https://www.rfc-editor.org/rfc/rfc9370>.
Acknowledgments
TODO acknowledge.
Authors' Addresses
Hu, Jun
Nokia
United States of America
Email: jun.hu@nokia.com
Yasufumi Morioka
NTT DOCOMO, INC.
Japan
Email: yasufumi.morioka.dt@nttdocomo.com
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