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Re: [TLS] Encrypting record headers: practical for TLS 1.3 after all?

Peter Gutmann <pgut001@cs.auckland.ac.nz> Mon, 30 November 2015 10:34 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: Bryan A Ford <brynosaurus@gmail.com>, "tls@ietf.org" <tls@ietf.org>
Thread-Topic: [TLS] Encrypting record headers: practical for TLS 1.3 after all?
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Date: Mon, 30 Nov 2015 10:34:27 +0000
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Subject: Re: [TLS] Encrypting record headers: practical for TLS 1.3 after all?
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Bryan A Ford <brynosaurus@gmail.com> writes:

>It would work just as well and in exactly the same way if the AEAD is
>replaced with the traditional Encrypt-then-MAC construction, for example.

No it wouldn't, unless the encrypt part is a stream cipher.  You're still
locked into using an AEAD stream cipher or the equivalent of an AEAD stream
cipher built with encrypt+MAC.  It won't work with, for example, the OCB AEAD
mode, or CBC + MAC.

Peter.

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