revamped sigs web pages

There have been several recent advances in Rabin-Williams signatures.
For example, 1536-bit security can now be achieved with 58-byte keys and
97-byte compressed signatures.

http://cr.yp.to/sigs.html now has several pages specifying a signature
system that combines all the latest techniques. It also has a new paper
proving that generic attacks on this system are as hard as factoring pq.

---D. J. Bernstein, Associate Professor, Department of Mathematics,
Statistics, and Computer Science, University of Illinois at Chicago