Re: [AVTCORE] Stephen Farrell's Discuss on draft-ietf-avtcore-srtp-aes-gcm-14: (with DISCUSS)

Magnus Westerlund <magnus.westerlund@ericsson.com> Thu, 19 February 2015 16:01 UTC

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Date: Thu, 19 Feb 2015 17:01:41 +0100
From: Magnus Westerlund <magnus.westerlund@ericsson.com>
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To: David McGrew <mcgrew@cisco.com>
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Cc: "draft-ietf-avtcore-srtp-aes-gcm@tools.ietf.org" <draft-ietf-avtcore-srtp-aes-gcm@tools.ietf.org>, IETF AVTCore WG <avt@ietf.org>, "avtcore-chairs@tools.ietf.org" <avtcore-chairs@tools.ietf.org>, The IESG <iesg@ietf.org>, Stephen Farrell <stephen.farrell@cs.tcd.ie>
Subject: Re: [AVTCORE] Stephen Farrell's Discuss on draft-ietf-avtcore-srtp-aes-gcm-14: (with DISCUSS)
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On 2015-02-15 15:09, David McGrew wrote:
> 
> My opinion is: it would be best to preserve the existing specification
> and implementation work, and retain all ten crypto suite definitions.  
> But if we want to make SRTP-AEAD be the first instance in which the IETF
> will  prioritize simplicity over variety and diversity, I’m good with
> that, because I certainly see the value of simplicity; then my
> recommendation would be to eliminate the four 12-octet authentication
> versions.  That would leave just six crypto suites, with two different
> modes of operation, two different key sizes, and two different tag
> lengths (but not all tag lengths for all modes), like this:
> 
>       srtp-crypto-suite-ext = "AEAD_AES_128_GCM"    /
>                               "AEAD_AES_256_GCM"    /
>                               "AEAD_AES_128_CCM"    /
>                               "AEAD_AES_256_CCM"    /
>                               "AEAD_AES_128_CCM_8"  /
>                               "AEAD_AES_256_CCM_8"  /
> 

Stephen, WG

Having looked at the feedback provided in this discussion so far, I
think the above set of 6 are a reasonable selection without unduly
limiting functionality, but removing the four least necessary profiles.

My proposal is that if no one is disagreeing with this in the next week
(Prior to Feb 26 at 16:30 UTC) we use it. If someone disagrees we hold a
discussion at the informal IESG telechat on how to proceed.

Cheers

Magnus Westerlund

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