re-enable SHA-1 for checksums
Optimized SHA-1 implementations aren't significantly slower than
MD5 and some folks (e.g. Tomas Doran) may already have SHA-1 in
place for their data.
A liberally licensed, GPL-compatible collection of SHA-1
primitives is available from one of the OpenSSL developers:
http://www.openssl.org/~appro/cryptogams/
It would be nice to allow the Perl Digest module to
transparently take advantage of architecture-specific
optimizations.
Note there is no standardized equivalent to the HTTP Content-MD5
header/trailer for any of the SHA variants, so verification for
replication/uploads may take significantly longer.
Requested-by: Tomas Doran