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Re: [TLS] Constant Finished (was Re: Kill Finished)

Martin Thomson <martin.thomson@gmail.com> Fri, 18 April 2014 20:21 UTC

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Date: Fri, 18 Apr 2014 13:21:05 -0700
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From: Martin Thomson <martin.thomson@gmail.com>
To: Michael D'Errico <mike-list@pobox.com>
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Subject: Re: [TLS] Constant Finished (was Re: Kill Finished)
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On 18 April 2014 12:09, Michael D'Errico <mike-list@pobox.com> wrote:
> IANAC but using a long-enough "magic number" for Finished seems fine
> if the handshake hash is moved to the key generator.
>
> But how long should that magic number be?  Currently we use 12 bytes,
> but should it be 16 or maybe even 32 bytes (when negotiating 256-bits
> of security)?  Can it be a simple string of zeros?

Why would it need to be anything at all?  As long as you can identify
the message as a Finished unambiguously, that should suffice.
HandshakeType is one byte.

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