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Re: [TLS] padding bug

Nikos Mavrogiannopoulos <nmav@gnutls.org> Tue, 10 September 2013 17:23 UTC

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From: Nikos Mavrogiannopoulos <nmav@gnutls.org>
To: Peter Gutmann <pgut001@cs.auckland.ac.nz>
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Subject: Re: [TLS] padding bug
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On Tue, Sep 10, 2013 at 11:56 AM, Peter Gutmann
<pgut001@cs.auckland.ac.nz> wrote:

>>Why not protect against future key recovery attacks by truncating the MAC?
>>After all IPSec does truncate the MAC to 96-bits for exactly the same reason
>>(see RFC2104 Section 5: Truncated output). Using the existing good practices
>>is a good thing.
> IPsec's truncation has nothing to do with security, it was done in order to
> fit the data into a 32-bit IP header boundary.  Since then an army of cargo-
> cult standards designers has mindlessly copied this design artefact into who
> knows how many other standards without understanding why it was done in the
> first place.  It's not "good practice", it's cargo-cult standards design.

Do you have any reference for that? RFC2104 and the paper it
references claim otherwise.

regards,
Nikos

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