Thanks all for your comments. Let me try to address your comments in one reply
1. Do we need to address both type-1 and type-2? I do think we need to address both because it is not entirely up to IPsec system to decide which type to use, it is also depends on the CA, and I don’t expect all CA will take same approach, and I also don’t expect CA could quickly change from one type to another (e.g. do type-2 first, and change to type-1 in short amount of time) 2. regarding security of using lamps composite signatures for type-2, I have asked John Grey (who is one author of draft-ietf-lamps-pq-composite-sigs) to take a look; the main concern that if attacker could get signature from individual component key, but my opinion is that it is ok in this context, as long as we add some requirements and clarification like following: a. the private key used in type-2 must be dedicated to IKEv2 hybrid authentication; they can’t be used to sign anything else, not even for induvial authentication; e.g. RSA key in hybrid auth can only be used for hybrid authentication, it can’t even be used to generate a RSA only AUTH payload. b. this is already in draft, but we could mandate the two certificates must have RelatedCertificate extension as specified in draft-ietf-lamps-cert-binding-for-multi-auth, so that two certificates are indeed issued in pairs for same end-entity 3. regarding using two AUTH payloads for type-2, I don’t think that’s simpler; first of all,, AFAIK, IKEv2 never support more than one AUTH payload, support multiple AUTH payloads break that and also requires additional logic; plus multiple AUTH payloads means additional encapsulation overhead 4. regarding why not using RFC4739, following are the reasons: a. save on round-trip since if using hybrid auth with hybrid key exchange (very likely), the total amount of exchange will be quite high b. with setup-2, we will need addition logic to bind two key/signature together if using rfc4739 c. trying to use a single solution for both type-1 and type-2 5. regarding draft-reddy-ipsecme-ikev2-pqc-auth, my draft is about hybrid authentication while my understanding of draft-reddy-ipsecme-ikev2-pqc-auth is about using ML-DSA/SLH-DSA as single auth, so they are addressing different problem From: Wang Guilin <Wang.Guilin=40huawei....@dmarc.ietf.org> Sent: Tuesday, November 5, 2024 5:58 PM To: Daniel Van Geest <daniel.vangeest=40cryptonext-security....@dmarc.ietf.org>; Scott Fluhrer (sfluhrer) <sfluhrer=40cisco....@dmarc.ietf.org>; tirumal reddy <kond...@gmail.com> Cc: ipsec <ipsec@ietf.org>; Wang Guilin <wang.gui...@huawei.com> Subject: [IPsec] Re: draft-hu-ipsecme-pqt-hybrid-auth CAUTION: This is an external email. Please be very careful when clicking links or opening attachments. See the URL nok.it/ext for additional information. Type-1 is more compatible with composite-signature in lamps. However, Type-2 is more flexible. Say, we have 4 traditional signature algorithms and 3 PQ signature algorithms. Then, we just need in total 7 algorithm IDs to denote these algorithms and all possible combinations of them. However, for Type-1, we need another 12 algorithm IDs just for all PQ/T combinations (not mentioning potential combinations of 3 or more algorithms). Also, the improving suugestions from Scott are interesting. Guilin From:Daniel Van Geest <daniel.vangeest=40cryptonext-security....@dmarc.ietf.org<mailto:daniel.vangeest=40cryptonext-security....@dmarc.ietf.org>> To:Scott Fluhrer (sfluhrer) <sfluhrer=40cisco....@dmarc.ietf.org<mailto:sfluhrer=40cisco....@dmarc.ietf.org>>;tirumal reddy <kond...@gmail.com<mailto:kond...@gmail.com>> Cc:ipsec <ipsec@ietf.org<mailto:ipsec@ietf.org>> Date:2024-11-05 17:28:00 Subject:[IPsec] Re: draft-hu-ipsecme-pqt-hybrid-auth And if the WG decides it wants to use Type-2 as specified in draft-hu-ipsecme-pqt-hybrid-auth, we should also advise LAMPS that we intend to abuse their composite signatures construction by reusing private keys within a composite signature and stand-alone. Perhaps the non-separability concerns aren't an issue in IKEv2 because the nonces make the signed content different for every signature. Daniel On 2024-11-05 4:31 p.m., Scott Fluhrer (sfluhrer) wrote: If we (as a working group) decide we want to use Type-1, we should advise the LAMPS working group that we intend to use their proposal. They provide a tool that we (IPSecME) uses; they need to know that there is demand for such a tool. From: tirumal reddy<kond...@gmail.com><mailto:kond...@gmail.com> Sent: Tuesday, November 5, 2024 9:17 AM To: Scott Fluhrer (sfluhrer) <sfluh...@cisco.com><mailto:sfluh...@cisco.com> Cc: ipsec@ietf.org<mailto:ipsec@ietf.org> Subject: Re: [IPsec] draft-hu-ipsecme-pqt-hybrid-auth I prefer Type-1 over Type-2, it seems more complicated to manage multiple certificates and the possibility of a downgrade attack . -Tiru On Tue, 5 Nov 2024 at 15:40, Scott Fluhrer (sfluhrer) <sfluhrer=40cisco....@dmarc.ietf.org<mailto:40cisco....@dmarc.ietf.org>> wrote: While I support the goals of this draft, I do not believe that the methods proposed are the most effective. It tries to merge Type-1 (certificates that include both classical and PQ keys) and Type-2 (two separate certificates) methods of providing public keys, however I believe it would be cleaner to keep them separate. For Type-1, if we use the ietf-lamps-pq-composite-sigs certificate format, then it is easy. That defines a new signature algorithm (which internally consists of a classical signature and a PQ signature pasted together, but we can ignore the internal details). We can use that as the signature method within the Auth payload, and hence the only changes we need to make to IKE is to recognize this new signature method. For Type-2 (multiple certificates), we need to request multiple certificates (which you do with the current proposal). However, it would be cleaner i(IMHO) if the other side just provided multiple CERT payloads and multiple AUTH payloads (rather than try to combine them). Each AUTH payload would contain the signature (based on the public key from the corresponding CERT payload) of the same data which is being signed now. The idea is that if we keep the fundamental structure of IKE authentication (just having multiple payloads when necessary), it may be easier for an existing IKE implementation to be extended. _______________________________________________ IPsec mailing list -- ipsec@ietf.org<mailto:ipsec@ietf.org> To unsubscribe send an email to ipsec-le...@ietf.org<mailto:ipsec-le...@ietf.org> _______________________________________________IPsec mailing list -- ipsec@ietf.org<mailto:ipsec@ietf.org>To unsubscribe send an email to ipsec-le...@ietf.org<mailto:ipsec-le...@ietf.org>
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