Haskell implementation of the Threefish block cipher and the various fun things you can do with it as specified by the Skein 1.3 paper. This currently includes:

• Threefish block cipher
• Skein hash function
• Skein-MAC
• PRNG
• Stream cipher
• Key derivation function

There's also a convenience module that puts it all together, for a simple interface to authenticated encryption.

For Skein 256, this package is about 35% slower than the wrapped C version in the skein package, so if you're only after the hash function you should use that package instead. The 512 bit variant is written in pure Haskell, and quite a bit slower still.