package Crypt::DES_EEE3;
use strict;
use Crypt::DES;
use Crypt::DES_EDE3;
use vars qw( $VERSION @ISA );
$VERSION = '0.01';
@ISA= qw(Crypt::DES_EDE3);
sub encrypt {
my($ede3, $block) = @_;
$ede3->{des3}->encrypt(
$ede3->{des2}->encrypt(
$ede3->{des1}->encrypt($block)
)
);
}
sub decrypt {
my($ede3, $block) = @_;
$ede3->{des1}->decrypt(
$ede3->{des2}->decrypt(
$ede3->{des3}->decrypt($block)
)
);
}
1;
__END__
=head1 NAME
Crypt::DES_EEE3 - Triple-DES EEE encryption/decryption
=head1 SYNOPSIS
use Crypt::DES_EEE3;
my $ede3 = Crypt::DES_EEE3->new($key);
$ede3->encrypt($block);
=head1 DESCRIPTION
I implements DES-EEE3 encryption. This is triple-DES
encryption where an encrypt operation is encrypt-encrypt-encrypt, and
decrypt is decrypt-decrypt-decrypt. This implementation uses I
to do its dirty DES work, and simply provides a wrapper around that
module: setting up the individual DES ciphers, initializing the keys,
and performing the encryption/decryption steps.
DES-EEE3 encryption requires a key size of 24 bytes.
You're probably best off not using this module directly, as the I
and I methods expect 8-octet blocks. You might want to use the
module in conjunction with I, for example. This would be
DES-EEE3-CBC, or triple-DES in outer CBC mode.
=head1 USAGE
=head2 $ede3 = Crypt::DES_EEE3->new($key)
Creates a new I object (really, a collection of three DES
ciphers), and initializes each cipher with part of I<$key>, which should be
at least 24 bytes. If it's longer than 24 bytes, the extra bytes will be
ignored.
Returns the new object.
=head2 $ede3->encrypt($block)
Encrypts an 8-byte block of data I<$block> using the three DES ciphers in
an encrypt-decrypt-encrypt operation.
Returns the encrypted block.
=head2 $ede3->decrypt($block)
Decrypts an 8-byte block of data I<$block> using the three DES ciphers in
a decrypt-encrypt-decrypt operation.
Returns the decrypted block.
=head2 $ede3->blocksize
Returns the block size (8).
=head2 $ede3->keysize
Returns the key size (24).
=head1 LICENSE
Crypt::DES_EEE3 is free software; you may redistribute it and/or modify
it under the same terms as Perl itself.
=head1 AUTHOR & COPYRIGHTS
Copyright 2003 by Kang-min Liu .
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
See
Thanks to the previous work of Crypt::DES_EDE3 by Benjamin Troot
=cut