package Object::Signature; use 5.005; use strict; use Storable 2.11 (); use Digest::MD5 2.00 (); use vars qw{$VERSION}; BEGIN { $VERSION = '1.07'; } sub signature { local $Storable::canonical = 1; Digest::MD5::md5_hex( Storable::nfreeze(shift) ); } 1; __END__ =pod =head1 NAME Object::Signature - Generate cryptographic signatures for objects =head1 SYNOPSIS # In your module package My::Module use base 'Object::Signature'; # In outside code my $Object = My::Module->new; print "Object Signature: " . $Object->signature; =head1 DESCRIPTION L 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 L and L. The object is fed to C to get a string, which is then passed to L to get a unique 32 character hexidecimal signature. =head1 METHODS =head2 signature The C method is the only method added to your class, and will generate a unique 32 hexidecimal signature for any object it is called on. =head1 SUPPORT All bugs should be filed via the bug tracker at L For other issues, or commercial enhancement or support, contact the author. =head1 TO DO =head2 Incremental Generation Currently has to generate the entire Storable string before digesting it. Would be nice if there was a way to incrementally Storablise and Digest in one pass so that it becomes much more memory efficient for large objects. =head2 Strengthen the Digest Algorithm Once the current (as of 2005) hashing controversy settles down, consider selecting a newer and more powerful hashing algorithm to replace MD5. Or offer alternatives depending on how important the security situation is, as MD5 is B fast (90 meg a second) and many more-secure ones are a lot slower (more than 10 times slower in some cases). On our side is the fact we use Storable. It should be B harder to create collisions when you don't control the string, only the structure B it goes through Storable. =head1 AUTHOR Adam Kennedy Eadamk@cpan.orgE =head1 SEE ALSO L, L =head1 COPYRIGHT Copyright 2004 - 2011 Adam Kennedy. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of the license can be found in the LICENSE file included with this module. =cut