SHA-1 recommendations

[Robert J. Hansen]

I've been a bit drowned by work, but I've had the opportunity lately to
draw up that list of recommendations I was threatening to inflict on
people.  :)

http://secret-alchemy.com/sha1

Comments and constructive feedback are welcome.  If there's interest,
then let's hammer out where it's deficient and what language needs to be
cleaned up, then get a final draft out, and start getting people in the
community to provide detached sigs for the page.