Re: [Monotone-devel] Re: fatal: Botan::PRNG_Unseeded

[Jack Lloyd]

On Tue, Apr 01, 2008 at 11:18:22AM +0200, Lapo Luchini wrote:
> Nathaniel Smith wrote:
> >>What else are random numbers used for? As I understand it, signing
> >>does not use random numbers, but maybe I'm confused.
> >
> >IIRC signatures do include random nonces -- I think this is one of the
> >things I picked up from Paul's rants about our cryptography -- but I
> >could be wrong too.
> 
> AFAIR he was complaining about the very fact that we currently use 
> signatures that don't, and proposed to change 'em =)
> 

Monotone uses EMSA3 (aka PKCS#1 v1.5), which is a deterministic
encoding. So for a fixed input, the same key will always produce the
same signature. (The generally accepted solution for RSA signature
padding is EMSA4 aka PSS, which is a randomized method).

-Jack