Re: Proposal for keying encrypted filesystem

[Edward Shushkin <edward@namesys.com>]

Edward Shushkin wrote:
> 
> Pierre Abbat wrote:
> >
> > On Saturday 29 March 2003 13:17, Edward Shushkin wrote:
> > > Any collision can be used by attacker for access to remained decrypted data
> > > in memory, so you should assign the *whole* output of any crypto-stable
> > > hash function (20 bytes for SHA1). If you use 19 bytes for ID, there is no
> > > any guarantee that someone can not find a collision easy.
> > > Edward.
> >
> > There isn't any guarantee with all 20 either,
> 
> Yes of course, but with all the 20 bytes I have a guarantee of SHA1 stability
> announced in appropriate papers, and I do have nothing for 19 bytes..

So from this standpoint I would rather prefer 16-byte ID created by full-grade md5,
then 19-byte ID created by restricted SHA1. Maybe this standpoint is too conservative, 
but this is right.. 

> 
>  it's just 256 times as hard to
> > find one and practically impossible. What about using the MD5 of the
> > passphrase for the key ID, and the SHA1 of the passphrase for the key?
> 
> Each secret key must be generated by special method which is specific for
> the used crypto algorithm, I think such methods are already exists, so we
> don't need to invent something new..
> 
> Edward.
> 
> >
> > phma
> > --
> > .i toljundi do .ibabo mi'afra tu'a do
> > .ibabo damba do .ibabo do jinga
> > .icu'u la ma'atman.