[cap-talk] use of hashcodes?

[Jack Lloyd]

On Sun, Feb 21, 2010 at 11:57:49AM -0500, Sandro Magi wrote:
> > We're talking about speeds in the range of 80-200 MB/s.  That's fast,
> > probably far faster than the network connection that Waterken will be
> > hooked up to.  I doubt that SHA256-HMAC is the performance bottleneck
> > in Waterken (though if you think it is, the best way to tell for sure
> > is to conduct careful performance measurements and share the results).
> 
> If you're really crazy about performance, or have limited hardware
> available, a MAC based on universal hashing (UMAC) seems to be gaining
> popularity [1], although they currently top out at 96-bit hashes. Their
> performance numbers are impressive [2].

There is also a newer variant called VMAC, which is even faster (on 64
bit machines, anyway) and can create longer tags. [1]

But it's worth noting that many UH-based schemes, and VMAC especially,
are quite fragile in the face of nonce reuse. [2]

-Jack

[1]: http://eprint.iacr.org/2006/037
[2]: http://www.ietf.org/mail-archive/web/cfrg/current/msg01336.html