This is not an interface (like "Digest::MD5") but a Perl implementation
of MD5. It is written in perl only and because of this it is slow but it
works without C-Code. You should use "Digest::MD5" instead of this
module if it is available. This module is only usefull for
computers where you cannot install "Digest::MD5" (e.g. lack of a
C-Compiler).

WWW: http://search.cpan.org/dist/Digest-Perl-MD5/