Re: [TLS] Include Speck block cipher?

Tom Ritter <tom@ritter.vg> Fri, 18 March 2016 14:46 UTC

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From: Tom Ritter <tom@ritter.vg>
Date: Fri, 18 Mar 2016 09:46:00 -0500
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To: Martin Thomson <martin.thomson@gmail.com>
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Cc: klimn@di.uoa.gr, Efthymios Iosifides <iosifidise@gmail.com>, "tls@ietf.org" <tls@ietf.org>
Subject: Re: [TLS] Include Speck block cipher?
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On 17 March 2016 at 21:09, Martin Thomson <martin.thomson@gmail.com>; wrote:
> On 18 March 2016 at 12:37, Mike Hamburg <mike@shiftleft.org>; wrote:
>> No.  The goal should be to remove ciphers, not add new ones, unless we have
>> a really compelling reason.
>
> A necessary, but sufficient set of reasons might include:
>
> 1. thorough cryptanalysis
> 2. advantages over existing ciphers on important metrics like security
> and speed, though this would likely need to be significant at this
> point
> 3. interest in implementation
>
> Speck is 0 from 3.

I might make it .5 for 3. Speck is specifically designed to be a
lightweight cipher for constrained devices. With RC4 dead in the water
- we don't have one of those. (Unless ChaCha20 is better than
Speck/Simon/related...)

That said, we'd still need the other 2.5 - and no, I'm not supporting it either.

-tom