Re: cprng_fast implementation benchmarks

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

On Wed, Apr 23, 2014 at 09:16:33AM -0400, Thor Lancelot Simon wrote:
> On Wed, Apr 23, 2014 at 10:57:59AM +0200, Joerg Sonnenberger wrote:
> > On Tue, Apr 22, 2014 at 11:59:38PM -0400, Thor Lancelot Simon wrote:
> > > I believe ChaCha8 is suitable for our purpose: we were previously 
> > > considering
> > > ciphers with, at most, 128-bit security, and even 6-round ChaCha has 
> > > 139-bit
> > > strength against the best currently known attack (at present, there is no
> > > attack better than brute force on ChaCha8, and the best attack on ChaCha7
> > > is 2^248).  ChaCha8 appears to be somewhat faster than the old arc4 
> > > implementation.
> > 
> > Sounds wrong. When I measured Salsa20/8, it was ~3 times faster than
> > RC4. Code can be found at
> > http://www.netbsd.org/~joerg/arc4random_salsa.c.
> 
> That's a libc implementation -- and were you calling it for 32 bits at a
> time, or bulk data?

I measured either case, extracting 32bits at a time vs doing larger
operations.

Joerg