# Copyright (C) 1995, 1996 Systemics Ltd (http://www.systemics.com/)
# Modifications are Copyright (c) 2000, W3Works, LLC
use vars
qw($VERSION @ISA @EXPORT @EXPORT_OK);
@ISA = qw(Exporter DynaLoader);
# Items to export into callers namespace by default
# Other items we are prepared to export if requested
bootstrap Crypt
::DES
$VERSION;
my ($package, $filename, $line, $subr) = caller(1);
croak
"Usage: $subr(@_)";
usage
("new DES key") unless @_ == 2;
$self->{'ks'} = Crypt
::DES
::expand_key
(shift);
usage
("encrypt data[8 bytes]") unless @_ == 2;
return Crypt
::DES
::crypt($data, $data, $self->{'ks'}, 1);
usage
("decrypt data[8 bytes]") unless @_ == 2;
return Crypt
::DES
::crypt($data, $data, $self->{'ks'}, 0);
Crypt::DES - Perl DES encryption module
The module implements the Crypt::CBC interface,
which has the following methods
Returns the size (in bytes) of the block cipher.
Returns the size (in bytes) of the key. Optimal size is 8 bytes.
my $cipher = new Crypt::DES $key;
This creates a new Crypt::DES BlockCipher object, using $key,
where $key is a key of C<keysize()> bytes.
my $cipher = new Crypt::DES $key;
my $ciphertext = $cipher->encrypt($plaintext);
This function encrypts $plaintext and returns the $ciphertext
where $plaintext and $ciphertext should be of C<blocksize()> bytes.
my $cipher = new Crypt::DES $key;
my $plaintext = $cipher->decrypt($ciphertext);
This function decrypts $ciphertext and returns the $plaintext
where $plaintext and $ciphertext should be of C<blocksize()> bytes.
my $key = pack("H16", "0123456789ABCDEF");
my $cipher = new Crypt::DES $key;
my $ciphertext = $cipher->encrypt("plaintex"); # NB - 8 bytes
print unpack("H16", $ciphertext), "\n";
Do note that DES only uses 8 byte keys and only works on 8 byte data
blocks. If you're intending to encrypt larger blocks or entire files,
please use Crypt::CBC in conjunction with this module. See the
Crypt::CBC documentation for proper syntax and use.
Also note that the DES algorithm is, by today's standard, weak
encryption. Crypt::Blowfish is highly recommended if you're
interested in using strong encryption and a faster algorithm.
Bruce Schneier, I<Applied Cryptography>, 1995, Second Edition,
published by John Wiley & Sons, Inc.
The implementation of the DES algorithm was developed by,
and is copyright of, Eric Young (eay@mincom.oz.au).
Other parts of the perl extension and module are
copyright of Systemics Ltd ( http://www.systemics.com/ ).
Cross-platform work and packaging for single algorithm
distribution is copyright of W3Works, LLC.
This single-algorithm package and cross-platform code is
maintained by Dave Paris <amused@pobox.com>.