Re: [ACRYPTO] new release of asynchronous crrypto layer.

[Herbert Xu <herbert@gondor.apana.org.au>]

Hi Evgeniy:

On Tue, Jul 11, 2006 at 09:31:57AM +0400, Evgeniy Polyakov wrote:
>
> > I noticed a bug in the ESP IV processing.  When you do ESP asynchronously,
> > you can no longer use the last block of the previous packet as the IV of
> > the next.  This is because the next packet may have started processing
> > before the last packet has even been finalised.
> 
> I cought that bug too, so IV being used is always copied into old_iv variable,
> so integrity is stated.

My point is that it is possible for two packets to use the same IV
under this scheme, which defeats the purpose of IVs.

> > A simple solution is to generate a random IV.
> 
> Yes, it could be done too.
> But actually neither random IV, nor IV created from encrypted previous packet, 
> nor IV created from unencrypted previous packet are forbidden by spec. 
> Initial implementation used constant IV there at all.

True.  However, using the same IV more than once is definitely not a good
idea.

Cheers,
-- 
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