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Re: [TLS] rfc7366: is encrypt-then-mac implemented?

Peter Gutmann <pgut001@cs.auckland.ac.nz> Wed, 29 October 2014 14:32 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: "<tls@ietf.org>" <tls@ietf.org>
Thread-Topic: [TLS] rfc7366: is encrypt-then-mac implemented?
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Date: Wed, 29 Oct 2014 14:32:30 +0000
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Subject: Re: [TLS] rfc7366: is encrypt-then-mac implemented?
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Nikos Mavrogiannopoulos <nmav@redhat.com> writes:

>I believe the description of Manuel and the NSS one [0] are pretty clear. If
>that bunch of implementations interoperates with eid.wx4.net then they don't
>follow the text in rfc7366.

I'm still not clear how NSS interprets this in the way it does.
TLSCipherText.length is the length of ENC(content + padding + padding_length),
which from section 6.2.3 of RFC 5246 is now the same as TLSCipherText.fragment
(since the MAC isn't part of GenericWhateverCipher any more).  So whether you
pass in TLSCipherText.length (as per the RFC) or TLSCipherText.fragment (as
NSS does) shouldn't make any difference because they're the same thing.

Peter.

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