Re: [TLS] TLS 1.3: Deterministic RSA-PSS and ECDSA

Brian Smith <brian@briansmith.org> Mon, 08 August 2016 19:54 UTC

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From: Brian Smith <brian@briansmith.org>
Date: Mon, 8 Aug 2016 09:54:30 -1000
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Subject: Re: [TLS] TLS 1.3: Deterministic RSA-PSS and ECDSA
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Martin Rex <mrex@sap.com>; wrote:
> The urban myth about the advantages of the RSA-PSS signature scheme
> over PKCS#1 v1.5 keep coming up.

PKCS#1 v1.5 is a partial-domain scheme, not a full-domain scheme. So,
RSA-PSS (without a salt, or with a fixed salt) might still have an
advantage over PKCS#1 v1.5 because it is a full-domain scheme.

> The advantages of the RSA-PSS signature scheme are limited to situations
> where the rightful owner of the private signing key is not supposed
> to have access to the bits of the private key (i.e. key kept in hardware).

RSA-PSS is the only (IETF) (proposed) standard for full-domain hashing
we have for RSA, AFAIK. This is why I think it might still make sense
to use it, in a deterministic fashion.

Cheers,
Brian
-- 
https://briansmith.org/