> I'm proposing it is time to change this to MUST NOT for 4307bis.
On 09/10/16 23:26, "IPsec on behalf of Paul Wouters"
<ipsec-boun...@ietf.org on behalf of p...@nohats.ca> wrote:
>Released a few days ago:
> A kilobit hidden SNFS discrete logarithm computation
> Joshua Fried and Pierrick Gaudry and Nadia Heninger and Emmanuel Thomé
> We perform a special number field sieve discrete logarithm
> computation in a 1024-bit prime field. To our knowledge, this
> is the first kilobit-sized discrete logarithm computation ever
> reported for prime fields. This computation took a little over
> two months of calendar time on an academic cluster using the
> open-source CADO-NFS software.
>Basically, this paper shows how to make a DH group of 1024 modp
>with a backdoor, in two months of academic computing resources,
>The paper mentions 5114 a few times:
> RFC 5114  specifies a number of groups for use with
> Diffie-Hellman, and states that the parameters were drawn
> from NIST test data, but neither the NIST test data  nor
> RFC 5114 itself contain the seeds used to generate the finite
> field parameters
> Both from this perspective, and from our more modern one, dismissing the
> risk of trapdoored primes in real usage appears to have been a mistake,
> as the apparent difficulties encountered by the trapdoor designer in
> turn out to be easily circumvented. A more conservative design decision
> for FIPS 186 would have required mandatory seed publication instead of
> making it optional. As a result, there are opaque, standardized
> and 2048-bit primes in wide use today that cannot be properly verified.
>This is the strongest statement yet that I've seen to not trust any
>of the RFC-5114 groups.
>The latest 4307bis document has these groups (22-24) as SHOULD NOT,
> Group 22, 23 and 24 or 1024-bit MODP Group with 160-bit, and
> 2048-bit MODP Group with 224-bit and 256-bit Prime Order Subgroup
> have small subgroups, which means that checks specified in the
> "Additional Diffie-Hellman Test for the IKEv2" [RFC6989] section
> 2.2 first bullet point MUST be done when these groups are used.
> These groups are also not safe-primes. The seeds for these groups
> have not been publicly released, resulting in reduced trust in
> these groups. These groups were proposed as alternatives for
> group 2 and 14 but never saw wide deployment. It is expected
> in the near future to be further downgraded to MUST NOT.
>I'm proposing it is time to change this to MUST NOT for 4307bis.
>Possibly, we should do this via SAAG in general, and then follow SAAG's
>advise in IPSECME.
>Is there _any_ reason why group 22-24 should not be MUST NOT ?
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