Re: [TLS] Fwd: I-D Action:draft-bmoeller-tls-falsestart-00.txt

Adam Langley <agl@google.com> Wed, 02 June 2010 15:48 UTC

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Date: Wed, 2 Jun 2010 11:47:47 -0400
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From: Adam Langley <agl@google.com>
To: mrex@sap.com
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Cc: tls@ietf.org, nagendra@cs.stanford.edu
Subject: Re: [TLS] Fwd: I-D Action:draft-bmoeller-tls-falsestart-00.txt
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On Wed, Jun 2, 2010 at 11:19 AM, Martin Rex <mrex@sap.com> wrote:
> In those application architectures, where the client app authentication
> is _not_ performed through a callback, but instead in a synchronous
> fashion after completion of the TLS handshake, TLS False Start will
> likely not be possible.

Certainly the design of some TLS code might make False Start awkward
or impossible. In those cases, it need not be supported.

> And I think that a client should _not_ try TLS False Start with
> a Server that lacks TLS Renegotiation Extension support (rfc5746).

I'm afraid that I don't see where the considerations of talking to a
server without the renegotiation extension, and using False Start,
interact. I think they are independent.

If an attacker were conducting a renegotiation attack, and altered the
handshake in any way (say, to remove a renegotiation extension), then
the client's Finished message would be rejected by the server.


AGL