Log Message:
Object::Signature is an abstract base class that you can inherit from in
order to allow your objects to generate unique cryptographic signatures.

The method used to generate the signature is based on Storable and
Digest::MD5. The object is fed to Storable::nfreeze to get a string,
which is then passed to Digest::MD5::md5_hex to get a unique 32
character hexidecimal signature.

WWW: http://search.cpan.org/dist/Object-Signature/