Re: [TLS] RSA-PSS in TLS 1.3

Hannes Mehnert <hannes@mehnert.org> Mon, 07 March 2016 13:51 UTC

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From: Hannes Mehnert <hannes@mehnert.org>
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Date: Mon, 7 Mar 2016 13:51:41 +0000
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Subject: Re: [TLS] RSA-PSS in TLS 1.3
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On 01/03/2016 11:32, Yoav Nir wrote:
>> On 1 Mar 2016, at 6:56 AM, Martin Thomson <martin.thomson@gmail.com> wrote:
>>
>> On 1 March 2016 at 04:32, Joseph Salowey <joe@salowey.net> wrote:
>>> We make RSA-PSS mandatory to implement (MUST implement instead of MUST
>>> offer).   Clients can advertise support for PKCS-1.5 for backwards
>>> compatibility in the transition period.
>>
>>> From my perspective, this is fine.  I would like to say that we won't
>> ever support PKCS#1.5 for TLS 1.3, but I think that I would rather
>> have users on 1.3 with PKCS#1.5 than have them stuck on 1.2.
>>
>> It seems like others are taking the position that we should say "MUST
>> NOT use PKCS#1.5”.  
> 
> I’d go even further. I’d remove the rsapss(4) value from SignatureAlgorithm, leaving just rsa(1), and say that in TLS 1.3 an RSA signature is PSS just as it was PKCS#1.5 in TLS 1.2.

I strongly agree to Yoav's proposal!  No need to have both RSA(-PKCS)
and RSA-PSS numbers in SignatureAlgorithms.


hannes