Re: Minimum length of secret key

James Couzens <[email protected]> Sat, 24 Jul 2004 04:17:12 -0700
Newsgroups gmane.mail.spam.srs.general
Organization 6o4.ca
Message-ID <1090667832.19361.144.camel@code3>
On Fri, 2004-07-23 at 21:06, Roger Moser wrote: 
> One rule in cryptography is to use the same key only once. But SRS (or SES)
> uses the same secret key for many different email addresses. So the secret
> key could be guessed, if it is too short.
> 
> Therefore my question to the crypto experts amongst you is:
> 
> What is minimum recommended length of the secret key used to generate the
> cryptographic hash so that the secret key cannot be guesses by cryptographic
> analysis of email addresses modified by SRS?

512 bits for SHA-160, and ideally they would be all truly random too.

Cheers,

James 


-- 
James Couzens,
Programmer
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