Re: [Unbearable] 0-RTT Token Binding: When to switch exporters?

Bill Cox <waywardgeek@google.com> Wed, 22 March 2017 01:20 UTC

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From: Bill Cox <waywardgeek@google.com>
Date: Tue, 21 Mar 2017 18:20:20 -0700
Message-ID: <CAH9QtQG9+wrbaPuDOqQw4N4K2SV_EE8CH4JX4xDJGkYgtYGHTQ@mail.gmail.com>
To: Nick Harper <nharper@google.com>
Cc: Andrei Popov <Andrei.Popov@microsoft.com>, IETF Tokbind WG <unbearable@ietf.org>
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Subject: Re: [Unbearable] 0-RTT Token Binding: When to switch exporters?
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I'm just now reading this thread.  A couple points: I agree with Nick that
switching exporters will hurt adoption rates of toke binding.  I think
servers should decide if they want to support 0-RTT token binding, and
accept this as part of the risk.

As for replay prevention, only about 1% of verified token binding headers
make it to our auth backend, meaning we have about a 100X reduction in
computing costs if we do replay prevention there.  TB replay prevention
belongs in the auth backend.

Bill