This code appears to have only cursory resemblance to Bruce Schneier's 
blowfish and twofish algorithms in that it too has a table-based decoder.
Derivation from FairKeys code by Jon Lech Johanson at nanocrew.net. 
If you don't know what that is, don't bother looking here further. This is
a Pure Perl implementation. I doubt there is any need for xs coding for 
what would mainly be processing 16 bytes at a time. This code is part of an 
ongoing effort to clone portions of the Apple iTMS in Perl for portability. 
See www.hymn-project.org for prior efforts by others.

WWW: http://search.cpan.org/dist/Crypt-AppleTwoFish/