SHA1.lhs is an implementation of the SHA-1 algorithm described in
FIPS PUB 180-1 (Federal Information Processing Standards Publication 180-1)
in Haskell. It works with both GHC and hugs (others not tested).

SHA1Sum.dpkg.lhs is an example application that uses SHA1.lhs with an
interface like that of MD5Sum.dpkg.lhs, which is a clone of the md5sum
utility that comes with dpkg, the Debian package manager.
Also has a -t for test option.