Re: [TLS] TLS 1.2 and CertificateRequest message

Nikos Mavrogiannopoulos <> Fri, 23 October 2009 16:39 UTC

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Date: Fri, 23 Oct 2009 19:39:57 +0300
From: Nikos Mavrogiannopoulos <>
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Subject: Re: [TLS] TLS 1.2 and CertificateRequest message
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Michael D'Errico wrote:
> I remember participating in the discussion that led to this design.  I
> argued that since we added a signature algorithms extension to allow
> negotiation of the client's preferred algorithms, it made the most
> sense to make the extension symmetric so the server could notify the
> client of its preferred algorithms in its hello message as well.
> There was opposition to my argument, that the list of algorithms belongs
> where it is needed, in the certificate request message.  The term
> "locality of reference" was thrown around as a justification.  Not being
> an official member of the working group, and since nobody else seemed to
> prefer my idea, I forfeited the point.

I believe you were correct then and this is really a drawback of TLS 1.2
comparing to TLS 1.x, x<2. My main concern is that it requires totally
different handling of handshake hashes, thus increasing code complexity
(and memory usage).