Crypt::Twofish - The Twofish Encryption Algorithm

Crypt-Twofish documentation Contained in the Crypt-Twofish distribution.

Index

Code Index:

NAME

Top

Crypt::Twofish - The Twofish Encryption Algorithm

SYNOPSIS

Top

use Crypt::Twofish;

$cipher = Crypt::Twofish->new($key);

$ciphertext = $cipher->encrypt($plaintext);

$plaintext = $cipher->decrypt($ciphertext);

DESCRIPTION

Top

Twofish is a 128-bit symmetric block cipher with a variable length (128, 192, or 256-bit) key, developed by Counterpane Labs. It is unpatented and free for all uses, as described at <URL:http://www.counterpane.com/twofish.html>.

This module implements Twofish encryption. It supports the Crypt::CBC interface, with the functions described below. It also provides an interface that is call-compatible with Crypt::Twofish 1.0, but its use in new code is strongly discouraged.

Functions

blocksize

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

keysize

Returns the size (in bytes) of the key. Although the module understands 128, 192, and 256-bit keys, it returns 16 for compatibility with Crypt::CBC.

new($key)

This creates a new Crypt::Twofish object with the specified key (which should be 16, 24, or 32 bytes long).

encrypt($data)

Encrypts blocksize() bytes of $data and returns the corresponding ciphertext.

decrypt($data)

Decrypts blocksize() bytes of $data and returns the corresponding plaintext.

SEE ALSO

Top

Crypt::CBC, Crypt::Blowfish, Crypt::TEA

ACKNOWLEDGEMENTS

Top

Nishant Kakani

For writing Crypt::Twofish 1.0 (this version is a complete rewrite).

Tony Cook

For making the module work under Activeperl, testing on several platforms, and suggesting that I probe for features via %Config.

AUTHOR

Top

Abhijit Menon-Sen <ams@toroid.org>

Copyright 2001 Abhijit Menon-Sen.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

Crypt-Twofish documentation Contained in the Crypt-Twofish distribution. 
# $Id: Twofish.pm,v 2.12 2001/05/21 17:38:01 ams Exp $
# Copyright 2001 Abhijit Menon-Sen <ams@toroid.org>

package Crypt::Twofish;

use strict;
use Carp;
use DynaLoader;
use vars qw( @ISA $VERSION );

@ISA = qw( DynaLoader );
$VERSION = '2.14';

bootstrap Crypt::Twofish $VERSION;

sub keysize   () { 16 }
sub blocksize () { 16 }

sub new
{
    my ($class, $key) = @_;

    croak "Usage: ".__PACKAGE__."->new(\$key)" unless $key;
    return Crypt::Twofish::setup($key);
}

sub encrypt
{
    my ($self, $data) = @_;

    croak "Usage: \$cipher->encrypt(\$data)" unless ref($self) && $data;
    $self->crypt($data, $data, 0);
}

sub decrypt
{
    my ($self, $data) = @_;

    croak "Usage: \$cipher->decrypt(\$data)" unless ref($self) && $data;
    $self->crypt($data, $data, 1);
}

# The functions below provide an interface that is call-compatible with
# the Crypt::Twofish 1.0 module. They do not, however, behave in exactly
# the same way: they don't pad keys, and cannot decrypt ciphertext which
# was written by the old module.
#
# (This interface is deprecated. Please use the documented interface
# instead).

sub Encipher
{
    my ($key, $keylength, $plaintext) = @_;

    require Crypt::CBC;
    my $cipher = Crypt::CBC->new($key, "Twofish");
    return $cipher->encrypt($plaintext);
}

sub Decipher
{
    my ($key, $keylength, $ciphertext, $cipherlength) = @_;

    require Crypt::CBC;
    my $cipher = Crypt::CBC->new($key, "Twofish");
    return $cipher->decrypt($ciphertext);
}

sub LastError    { "";    }
sub CheckTwofish { undef; }

1;

__END__