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

Manuel Pégourié-Gonnard <mpg@elzevir.fr> Tue, 07 October 2014 14:02 UTC

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Date: Tue, 07 Oct 2014 16:02:52 +0200
From: Manuel Pégourié-Gonnard <mpg@elzevir.fr>
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To: James Cloos <cloos@jhcloos.com>, Nikos Mavrogiannopoulos <n.mavrogiannopoulos@gmail.com>
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Subject: Re: [Cfrg] RGLC on draft-irtf-cfrg-chacha20-poly1305-01.txt
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On 07/10/2014 15:20, James Cloos wrote:
>>>>>> "NM" == Nikos Mavrogiannopoulos <n.mavrogiannopoulos@gmail.com> writes:
> 
> NM> Would you really want to use an AEAD cipher for backup encryption in a
> NM> single pass? I mean a single bit corruption in 128 Gigs and you lost
> NM> everything as authentication would fail.
> 
> One should only loose the block which failed auth.
> 
> Ie, each block should be treated separately.
> 
I'm sorry if I'm missing something painfully obvious, but if each block is
treated separately, then why do you need a counter larger than 32 bits?

Manuel.

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