Initial Commit

database/perl/vendor/lib/Crypt/DES_EDE3.pm

@@ -0,0 +1,118 @@
+# $Id: DES_EDE3.pm,v 1.2 2001/09/15 03:41:09 btrott Exp $
+
+package Crypt::DES_EDE3;
+use strict;
+
+use Crypt::DES;
+use vars qw( $VERSION );
+$VERSION = '0.01';
+
+sub new {
+    my $class = shift;
+    my $ede3 = bless {}, $class;
+    $ede3->init(@_);
+}
+
+sub keysize   { 24 }
+sub blocksize { 8 }
+
+sub init {
+    my $ede3 = shift;
+    my($key) = @_;
+    for my $i (1..3) {
+        $ede3->{"des$i"} = Crypt::DES->new(substr $key, 8*($i-1), 8);
+    }
+    $ede3;
+}
+
+sub encrypt {
+    my($ede3, $block) = @_;
+    $ede3->{des3}->encrypt(
+        $ede3->{des2}->decrypt(
+            $ede3->{des1}->encrypt($block)
+        )
+    );
+}
+
+sub decrypt {
+    my($ede3, $block) = @_;
+    $ede3->{des1}->decrypt(
+        $ede3->{des2}->encrypt(
+            $ede3->{des3}->decrypt($block)
+        )
+    );
+}
+
+1;
+__END__
+
+=head1 NAME
+
+Crypt::DES_EDE3 - Triple-DES EDE encryption/decryption
+
+=head1 SYNOPSIS
+
+    use Crypt::DES_EDE3;
+    my $ede3 = Crypt::DES_EDE3->new($key);
+    $ede3->encrypt($block);
+
+=head1 DESCRIPTION
+
+I<Crypt::DES_EDE3> implements DES-EDE3 encryption. This is triple-DES
+encryption where an encrypt operation is encrypt-decrypt-encrypt, and
+decrypt is decrypt-encrypt-decrypt. This implementation uses I<Crypt::DES>
+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-EDE3 encryption requires a key size of 24 bytes.
+
+You're probably best off not using this module directly, as the I<encrypt>
+and I<decrypt> methods expect 8-octet blocks. You might want to use the
+module in conjunction with I<Crypt::CBC>, for example. This would be
+DES-EDE3-CBC, or triple-DES in outer CBC mode.
+
+=head1 USAGE
+
+=head2 $ede3 = Crypt::DES_EDE3->new($key)
+
+Creates a new I<Crypt::DES_EDE3> 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_EDE3 is free software; you may redistribute it and/or modify
+it under the same terms as Perl itself.
+
+=head1 AUTHOR & COPYRIGHTS
+
+Crypt::DES_EDE3 is Copyright 2001 Benjamin Trott, ben@rhumba.pair.com. All
+rights reserved.
+
+=cut