Hi Martin, AES_256_CCM_8 was not in the first versions of the draft but added later after request from IoT people (probably afraid of quantum computers).
While I think it makes very much sense to have short tags in wireless radio, I do not know how large need there is for AES-256 in IoT for constrained devices, or how large the need would be to truncate the tag in these cases. My current understanding is that Grover’s algorithm may never be more cost-effective than a cluster of classical computers, and that quantum computers therefore likely do not affect the lifetime of AES-128. I do not have any strong opinions regarding keeping AES_256_CCM_8 or not. We should not give the impression that AES-256 is needed for practical resistance to quantum computers anytime soon, it is however a requirement for use by US government. Agree that AES_128_CCM_8 and AES_256_CCM seems like the best choices in most cases. Cheers, John On 12/08/16 08:29, "TLS on behalf of Martin Thomson" <tls-boun...@ietf.org on behalf of martin.thom...@gmail.com> wrote: >Looking at those emails, I am prompted to wonder if anyone can justify >the existence of a ciphersuite with a double-sized key and half-sized >authentication tag. RFC 6655 doesn't really explain how that is a >useful thing. > >On 10 August 2016 at 19:33, Nikos Mavrogiannopoulos <n...@redhat.com> >wrote: >> On Tue, 2016-08-09 at 14:45 -0400, Sean Turner wrote: >>> All, >>> >>> We've received a request for early IANA assignments for the 6 cipher >>> suites listed in https://datatracker.ietf.org/doc/draft-ietf-tls-ecdh >>> e-psk-aead/. Please respond before August 23rd if you have concerns >>> about early code point assignment for these cipher suites. >> >> I have previously raised an issue [0] on these ciphersuites. The same >> requirement was noted also by Peter Dettman as something special in >> [1]. However, there has been no reaction from the authors (now in CC). >> >> regards, >> Nikos >> >> [0]. >>https://mailarchive.ietf.org/arch/msg/tls/4PZsc_Dy-aT299BYrlBKvZs0BOQ >> [1]. >>https://mailarchive.ietf.org/arch/msg/tls/onEkdgH30eZgWs8v5Rp-CUqCHds >> >> _______________________________________________ >> TLS mailing list >> TLS@ietf.org >> https://www.ietf.org/mailman/listinfo/tls > >_______________________________________________ >TLS mailing list >TLS@ietf.org >https://www.ietf.org/mailman/listinfo/tls _______________________________________________ TLS mailing list TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls
