[Cryptech Core] dnssec signer

[Rob Austein]

At Wed, 15 Jul 2015 23:23:39 +0300, ????? ????? wrote:
> 
> Do I get it right, that for SHA-256 internal state is defined by eight 
> 32-bit words (h0..h7)? Saving state implies reading current digest value 
> and saving it somewhere (not in FPGA), while restoring state means 
> initializing h0..h7 registers with some arbitrary values, right?

Er, I'm guessing you mean the H registers (H0..H7); "h" is part of a
different series of registers (a..h).

I *think* you're correct that the state we care about is the H
registers.  At least, that's what I get from reading the Python model;
I haven't studied the internal details of the algorithm (and don't
have time to do so before leaving for the airport tonight).

> I've actually taken a look at core/hash/sha256, I think it is possible 
> to add state restore functionality, if I understand it correctly. If Rob 
> and Paul can help me compile and test modified sha256.v in hardware, I 
> will try to fix it on Friday.

Sure, we can try that on Friday unless something more urgent comes up.