From: Johnathan Corgan <jcorgan@aeinet.com>
Date: Thu, 27 Jul 95 09:06:49 PDT
To: Andy Brown <asb@nexor.co.uk>
Subject: Re: Encrypting block driver for Linux...need some advice
In-Reply-To: <Pine.SOL.3.91.950727104038.17605B-100000@eagle.nexor.co.uk>
Message-ID: <Pine.LNX.3.91.950727085755.104A-100000@comet.aeinet.com>
MIME-Version: 1.0
Content-Type: text/plain


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On Thu, 27 Jul 1995, Andy Brown wrote:

> Your scheme should be OK.  If you'd chosen the same IV for each sector 
> then identical sectors would encrypt the same.  If I remember rightly 
> then having a known IV only affects the security of the first block, 
> after that the ciphertext chaining comes into effect.

I suspected as much.  I don't see how a known IV affects the security of the
first block even (and perhaps I'm exposing some real crypto-ignorance here
:).

Someone pointed out in private mail that the SFS docs have a good section on
IV selection techniques...I'll go off and read those.

==
Johnathan Corgan       "For the first time in history, it is possible to
jcorgan@aeinet.com      have absolute privacy over arbitrary distances."
PGP Key Fingerprint:    4F 28 69 B8 76 2E 42 3E  8B 4C 12 BB 3A 43 D4 07


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