Re: [Cfrg] RGLC on draft-irtf-cfrg-chacha20-poly1305-01.txt

Peter Gutmann <pgut001@cs.auckland.ac.nz> Tue, 07 October 2014 10:28 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: "'cfrg@irtf.org'" <cfrg@irtf.org>
Thread-Topic: [Cfrg] RGLC on draft-irtf-cfrg-chacha20-poly1305-01.txt
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Date: Tue, 7 Oct 2014 10:27:44 +0000
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Subject: Re: [Cfrg] RGLC on draft-irtf-cfrg-chacha20-poly1305-01.txt
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Nikos Mavrogiannopoulos <n.mavrogiannopoulos@gmail.com> writes:

>Would you really want to use an AEAD cipher for backup encryption in a single
>pass? I mean a single bit corruption in 128 Gigs and you lost everything as
>authentication would fail. 

You wouldn't lose anything, you'd just get a notification that some of the
data was corrupted.  In fact if you use one of the CTR-mode-based AEAD
constructions, which are just KSG ciphers, then you could flip all sorts of
bits with minimal data loss.

Peter.