[boost] Re: Proposal: random number library

From: Jens Maurer (jmaurer_at_[hidden])
Date: 2000-02-22 13:28:56

Reid Sweatman wrote: 
> It may whiff of crypto, but I don't think anyone (even the NSA, although who
> knows? <g>) could legitimately claim that a PRNG routine fell under the
> Munitions Act, since crypto is hardly the only thing that requires good
> PRNG's.

There is a difference in quality between a PRNG for simulations and one
for cryptographic applications.  For simulations, you ask questions such
as "does this PRNG have good statistical properties, i.e. does it pass
the D.E. Knuth tests?" and "is it fast (enough)?".
However, for cryptographic applications, you must make sure that nobody
can guess your random numbers even if he knows some parts of the sequence
of your PRNG.  Execution speed is secondary.  Read the paper about
Yarrow-160 on www.counterpane.com for a cryptographer's approach to PRNGs.
In this paper, the authors suggest using SHA-1 and Triple-DES for
hashing.  Triple-DES certainly qualifies as an encryption algorithm.
Besides, it's not only the US ITAR regulations. In France, for example,
use of cryptography requires an individual license from the government.
Look at your favourite Netscape mirror for the special crypto-disabled
"France" version.

Jens Maurer.