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Re: [TLS] Proposed text for removing renegotiation

Martin Thomson <martin.thomson@gmail.com> Wed, 28 May 2014 17:02 UTC

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Date: Wed, 28 May 2014 10:02:00 -0700
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From: Martin Thomson <martin.thomson@gmail.com>
To: mrex@sap.com
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Subject: Re: [TLS] Proposed text for removing renegotiation
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On 27 May 2014 17:44, Martin Rex <mrex@sap.com> wrote:
> Conceptually, the TLS session cache is readonly after an entry
> is created, and that is GOOD, i.e. full TLS handshakes create new,
> distict session cache entries, and abbreviated TLS handshakes resume
> existing session cache entries and *NEVER* modify them.

That's a good point.  Something that I missed.  A resumption handshake
would have to include an epoch from the previous session.  That number
would need to be incremented with each update of the master secret.

Alternatively, and I think preferably, we could allow (or require)
servers to send the NewSessionTicket message when they update the
master secret, so that there isn't a master secret lying around
anywhere.

Of course, if you want to argue for unmodifiable state, then maybe you
can provide stronger justification than that.

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