Re: [Cfrg] A little room for AES-192 in TLS?
"Stanislav V. Smyshlyaev" <smyshsv@gmail.com> Mon, 16 January 2017 18:09 UTC
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Date: Mon, 16 Jan 2017 21:09:01 +0300
From: "Stanislav V. Smyshlyaev" <smyshsv@gmail.com>
In-Reply-To: <D4A2B50D.7E040%kenny.paterson@rhul.ac.uk>
References: <20170115205926.853FB60A6D@jupiter.mumble.net> <1484577818.5104.1.camel@quad> <D4A2A7CE.57FDF%john.mattsson@ericsson.com> <CABcZeBPGxT=9iiChy4PxD_zMHWcHU=AhCLoe7wEHHtryw2rfwg@mail.gmail.com> <D4A2B50D.7E040%kenny.paterson@rhul.ac.uk>
To: "Paterson, Kenny" <Kenny.Paterson@rhul.ac.uk>, Eric Rescorla <ekr@rtfm.com>, John Mattsson <john.mattsson@ericsson.com>
Archived-At: <https://mailarchive.ietf.org/arch/msg/cfrg/53fIlVhs85zYIko_j1GR5BftduE>
Cc: cfrg@irtf.org, Leonard den Ottolander <leonard-lists@den.ottolander.nl>
Subject: Re: [Cfrg] A little room for AES-192 in TLS?
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Dear colleagues, Thank you for this discussion! To be honest, I cannot imagine an adversary model (with any relation to practice) for TLS, for which AES-192 would be useful - I agree with Kenny about related-key attacks here. So I don't see any strong points to add AES-192 to 1.3 too. Best regards, Stanislav Smyshlyaev Исходное сообщение От: Paterson, Kenny Отправлено: понедельник, 16 января 2017 г., 20:37 Кому: Eric Rescorla; John Mattsson Копия: cfrg@irtf.org; Leonard den Ottolander Тема: Re: [Cfrg] A little room for AES-192 in TLS? Hi, On 16/01/2017 16:27, "Cfrg on behalf of Eric Rescorla" <cfrg-bounces@irtf.org on behalf of ekr@rtfm.com> wrote: >Generally, I think the sense of the WG is to try to minimize the number >of ciphers/suits. > > >Speaking personally, what would make me be in favor of adding AES-192 >would be >some statement from CFRG that they thought that it was significantly >stronger than >AES-256. Absent that, I think it would be better to leave it out of TLS. Speaking without my co-chair's hat on... I don't think related-key attacks are a particular concern for TLS. So I don't think there's a strong argument for supporting AES-192 in the TLS 1.3 protocol specification. Anyone else from CFRG have an opinion on this? Cheers Kenny > > >-Ekr > > > > >On Mon, Jan 16, 2017 at 7:59 AM, John Mattsson ><john.mattsson@ericsson.com> wrote: > >Note that there are trivial generic related-key attacks on AES-192 with #K >= D = T = M = 2^96 > >http://dx.doi.org/10.1080/0161-118791861749 > >Regards, >John > > >On 2017-01-16, 15:43, "Cfrg on behalf of Leonard den Ottolander" ><cfrg-bounces@irtf.org on behalf of >leonard-lists@den.ottolander.nl> wrote: > >>On Sun, 2017-01-15 at 20:59 +0000, Taylor R Campbell wrote: >>> Only very unusual protocols ever use related keys. In sensible >>> protocols, every key is drawn independently uniformly at random. >> >>Protocols that are designed to use related keys? I hope not! >> >>Compare >http://eprint.iacr.org/2009/317 <http://eprint.iacr.org/2009/317> 4.1 >Related-key attack model: >> >>"Compared to other cryptanalytic attacks in which the attacker can >>manipu- >>late only the plaintexts and/or the ciphertexts the choice of the >>relation between >>secret keys gives additional degree of freedom to the attacker. The >>downside of >>this freedom is that such attacks might be harder to mount in practice. >>Still, >>designers usually try to build "ideal" primitives which can be >>automatically used >>without further analysis in the widest possible set of applications, >>protocols, or >>modes of operation. Thus resistance to such attacks is an important >>design goal >>for block ciphers, and in fact it was one of the stated design goals of >>the Rijndael >>algorithm, which was selected as the Advanced Encryption Standard." >> >>So the question remains if indeed AES-192 is inherently more resistant >>to this kind of attack (more of an "ideal primitive" in this respect) >>than AES-256 or do I read too much in the remark "the key schedule of >>AES-192 has better diffusion" in 6 Attack on AES-192? >> >>Regards, >>Leonard. >> >>-- >>mount -t life -o ro /dev/dna /genetic/research >> >> >> >>_______________________________________________ >>Cfrg mailing list >>Cfrg@irtf.org >>https://www.irtf.org/mailman/listinfo/cfrg > >_______________________________________________ >Cfrg mailing list >Cfrg@irtf.org >https://www.irtf.org/mailman/listinfo/cfrg > > > > > > > _______________________________________________ Cfrg mailing list Cfrg@irtf.org https://www.irtf.org/mailman/listinfo/cfrg
- [Cfrg] A little room for AES-192 in TLS? Leonard den Ottolander
- Re: [Cfrg] A little room for AES-192 in TLS? Taylor R Campbell
- Re: [Cfrg] A little room for AES-192 in TLS? Leonard den Ottolander
- Re: [Cfrg] A little room for AES-192 in TLS? Taylor R Campbell
- Re: [Cfrg] A little room for AES-192 in TLS? Leonard den Ottolander
- Re: [Cfrg] A little room for AES-192 in TLS? John Mattsson
- Re: [Cfrg] A little room for AES-192 in TLS? Eric Rescorla
- Re: [Cfrg] A little room for AES-192 in TLS? Paterson, Kenny
- Re: [Cfrg] A little room for AES-192 in TLS? Stanislav V. Smyshlyaev
- Re: [Cfrg] A little room for AES-192 in TLS? Tony Arcieri
- Re: [Cfrg] A little room for AES-192 in TLS? Leonard den Ottolander
- Re: [Cfrg] A little room for AES-192 in TLS? Ilari Liusvaara
- Re: [Cfrg] A little room for AES-192 in TLS? Salz, Rich
- Re: [Cfrg] A little room for AES-192 in TLS? John Mattsson
- Re: [Cfrg] A little room for AES-192 in TLS? Tony Arcieri
- Re: [Cfrg] A little room for AES-192 in TLS? Leonard den Ottolander
- Re: [Cfrg] A little room for AES-192 in TLS? Salz, Rich
- Re: [Cfrg] A little room for AES-192 in TLS? Yoav Nir
- Re: [Cfrg] A little room for AES-192 in TLS? William Whyte
- Re: [Cfrg] A little room for AES-192 in TLS? Tony Arcieri
- Re: [Cfrg] A little room for AES-192 in TLS? Phillip Hallam-Baker
- Re: [Cfrg] A little room for AES-192 in TLS? Ted Krovetz
- Re: [Cfrg] A little room for AES-192 in TLS? Joan Daemen
- Re: [Cfrg] A little room for AES-192 in TLS? Leonard den Ottolander
- Re: [Cfrg] A little room for AES-192 in TLS? Phillip Hallam-Baker
- Re: [Cfrg] A little room for AES-192 in TLS? Leonard den Ottolander
- Re: [Cfrg] A little room for AES-192 in TLS? Phillip Hallam-Baker
- Re: [Cfrg] A little room for AES-192 in TLS? Paterson, Kenny