NAME

Crypt::Shark - Crypt::CBC compliant block cipher

ABSTRACT

Shark is 64-bit block cipher that accepts a 128-bit key.

SYNOPSIS

    use Crypt::Shark;

    $cipher = new Crypt::Shark $key;
    $ciphertext = $cipher->encrypt($plaintext);
    $plaintext  = $cipher->decrypt($ciphertext);

DESCRIPTION

Shark is 64-bit block cipher that accepts a 128-bit key. It was designed by Vincent Rijmen, Joan Daemen, Bart Preneel, Antoon Bosselaers, and Erik De Win.

This module supports the Crypt::CBC interface, with the following functions.

Functions

blocksize

Returns the size (in bytes) of the block (8, in this case).

keysize

Returns the size (in bytes) of the key (16, in this case).

encrypt($data)

Encrypts 8 bytes of $data and returns the corresponding ciphertext.

decrypt($data)

Decrypts 8 bytes of $data and returns the corresponding plaintext.

EXAMPLE 1

    #!/usr/local/bin/perl

    use diagnostics;
    use strict;
    use warnings;
    use Crypt::Shark;

    # key must be 16 bytes long
    my $key = "0123456789abcdef";

    my $cipher = new Crypt::Shark $key;

    print "blocksize = ", $cipher->blocksize, " bytes \n";
    print "keysize = ", $cipher->keysize, " bytes \n";

    # block must be 8 bytes long
    my $plaintext1 = "01234567";

    my $ciphertext = $cipher->encrypt($plaintext1);
    my $plaintext2 = $cipher->decrypt($ciphertext);

    print "Decryption OK\n" if ($plaintext1 eq $plaintext2);

EXAMPLE 2

    #!/usr/local/bin/perl

    use diagnostics;
    use strict;
    use warnings;
    use Crypt::CBC;  # CBC automatically loads Shark for us

    # when using Crypt::CBC, key may be of ANY length
    my $key = "0123456789abcdef";

    # IV must be exactly 16 bytes long
    my $IV = pack "H16", 0;

    my $cipher = Crypt::CBC->new({'key' => $key,
                                  'cipher' => 'Shark',
                                  'iv' => $IV,
                                  'regenerate_key' => 1,
                                  'padding' => 'standard',
                                  'prepend_iv' => 0
                                });

    # when using Crypt::CBC, plaintext may be of ANY length
    my $plaintext1 = "This is a test";

    my $ciphertext = $cipher->encrypt($plaintext1);
    my $plaintext2 = $cipher->decrypt($ciphertext);

    print "Decryption OK\n" if ($plaintext1 eq $plaintext2);

MORE EXAMPLES

See Crypt::CBC for more examples using CBC mode. See also the "examples" and "t" directories for some more examples.

SEE ALSO

Crypt::Khazad, Crypt::Misty1, Crypt::Anubis, Crypt::Noekeon, Crypt::Skipjack, Crypt::Camellia, Crypt::Square, and Crypt::Rainbow.

COPYRIGHT AND LICENSE

Copyright 2003 by Julius C. Duque. Please read contact.html that comes with this distribution for details on how to contact the author.

This library is free software; you can redistribute it and/or modify it under the same terms as the GNU General Public License.