Re: [PATCH/proposal] dm-crypt: add digest-based iv generation mode

[Jean-Luc Cooke <jlcooke@certainkey.com>]

On Thu, Feb 19, 2004 at 11:18:35AM -0800, Andrew Morton wrote:
> Christophe Saout <christophe@saout.de> wrote:
> >
> > Hello,
> > 
> > since some people keep complaining that the IV generation mechanisms
> > supplied in cryptoloop (and now dm-crypt) are insecure, which they
> > somewhat are, I just hacked a small digest based IV generation mechanism.
> > 
> > It simply hashes the sector number and the key and uses it as IV.
> > 
> > You can specify the encryption mode as "cipher-digest" like aes-md5 or
> > serpent-sha1 or some other combination.

As for naming the cipher-hash as "aes-sha256", why not just go all the way
and specify the mode of operation as well?

cipher-hash-modeop example: aes-sha256-cbc

As for hashing the hey etc.  You should be using HMAC for that.
  Christophe - would you like to change your patch to use HMACs?
  http://www.faqs.org/rfcs/rfc2104.html

Cheers,

JLC

> hmm.
> 
> > Consider this as a proposal, I'm not a crypto expert.
> 
> Me either.  But I believe that there are crypto-savvy people reading this
> list.  Help would be appreciated.
> 
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