=head1 NAME

Tiger - Perl interface to the Tiger Hash Algorithm

=head1 SYNOPSIS

    use Tiger;

    $context = new Tiger;
    $context->reset();

    $context->add(LIST);
    $context->addfile(HANDLE);

    $digest = $context->digest();
    $string = $context->hexdigest();

    $digest = $context->hash($string);
    $string = $context->hexhash($string);

=head1 DESCRIPTION

The B<Tiger> module allows you to use the Tiger hash algorithm
developed by Ross Anderson and Eli Biham in Perl programs.

A new Tiger context object is created with the B<new> operation.
Multiple simultaneous digest context can be maintained if desired.
The context is updated with the B<add> operation which adds the
strings contained in the I<LIST> parameter.

The final message digest value is returned by the B<digest> operation
as a 24-byte binary string. This operation delivers the result of
operations since the last B<new> or B<reset> operation. Once the
operation has been performed, the context must be B<reset> before
being used to calculate another digest value.

Several convenience functions are also provided. The B<addfile>
operation takes an open file-handle and reads it until end-of file in
8192-byte blocks adding the contents to the context. The B<hexdigest>
operation calls B<digest> and returns the result as a printable string
of hexadecimal digits in eight-digit groups. The B<hash> operation
performs the complete series of steps: B<reset>, B<add>, B<digest> on
the supplied scalar value, and returns the result as a 24-byte binary
string. The B<hexhash> operation does the same thing, but returns the
result in the format of the B<hexdigest> operation.

=head1 NOTE

The Tiger extension may be redistributed either under the GPL or the
Perl Artistic License.  The Tiger code has been appropriated from the
GNU Privacy Guard, and slightly modified to interface with Perl.

=head1 AUTHOR

The Tiger interface was written by Rafael Sevilla
(C<dido@pacific.net.ph>), shamelessly stealing from the SHA interface
written by Uwe Hollerbach (C<uh@alumni.caltech.edu>).

For more information on Tiger see:

http://www.cs.technion.ac.il/~biham/Reports/Tiger/


