Blowfish is a published algorithm written by Bruce Schneier Unlike
IDEA or DES etc. there are no patent implications in using this
algorithm.

It uses anywhere between a 64 bit and a 448 bit key. The transform
itself is fast and operates on a 64 bit block, and most of the
calculation time is in initialising the context with the key data.

The _PP name comes from the fact that this implementation is Pure
Perl, and will not have any compatibility problems.

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