Re: [TLS] Encryption of TLS 1.3 content type

Colm MacCárthaigh <colm@allcosts.net> Mon, 28 July 2014 14:54 UTC

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Date: Mon, 28 Jul 2014 07:54:00 -0700
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From: =?UTF-8?Q?Colm_MacC=C3=A1rthaigh?= <colm@allcosts.net>
To: Nikos Mavrogiannopoulos <nmav@redhat.com>
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Subject: Re: [TLS] Encryption of TLS 1.3 content type
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On Mon, Jul 28, 2014 at 1:55 AM, Nikos Mavrogiannopoulos
<nmav@redhat.com> wrote:
> Are there any pointers to these attacks? Will these attacks be countered
> with such a change? I believe not as alert messages consist of only two
> bytes and will be distinct from any other higher protocol messages
> transferred by the TLS record protocol.

This is not the case. Firstly, even with a stream cipher it doesn't
distinguish the message from a 2 byte application data message. But
most ciphers are block ciphers, and so the true length is fuzzed by
about an order of magnitude.

-- 
Colm