Re: [TLS] Using RSA PSS in TLS

Johannes Merkle <johannes.merkle@secunet.com> Mon, 28 October 2013 13:28 UTC

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Date: Mon, 28 Oct 2013 14:27:47 +0100
From: Johannes Merkle <johannes.merkle@secunet.com>
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Subject: Re: [TLS] Using RSA PSS in TLS
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> IMO it is not necessary to define new cipher suites. The semantics of "RSA" in cipher suites (and KeyExchangeAlgorithm
> indicated in the the server key exchange messages) could be widened to comply with both PKCS#1v1.5 and PSS, and the use
> of PSS would be defined eligible only if it has been signaled in the "signature_algorithms" extension by the other peer.

The signature algorithm that was actually used is specified (within a DigitallySigned struct) by an
SignatureAndHashAlgorithm identifier of the same type as used in the "signature_algorithms" extension. Thus, the code
points in this registry can be used for both signaling support of PSS and specifying the PSS as the signature algorithm
that was actually selected.

-- 
Johannes