To store passwords securely, they should be salted, then hashed with a slow
hash function. This library uses PBKDF1-SHA256, and handles all the details.
It uses the cryptohash package for speed; if you need a pure Haskell library,
pwstore-purehaskell has the exact same API, but uses only pure Haskell.
It is about 25 times slower than this package, but still quite usable.