DES(3) User Contributed Perl Documentation DES(3)

Crypt::DES - Perl DES encryption module

use Crypt::DES;
my $key = pack("H16", "0123456789ABCDEF");
my $cipher = Crypt::DES->new($key);
my $ciphertext = $cipher->encrypt($plaintext);
my $plaintext = $cipher->decrypt($ciphertext);

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

This creates a new Crypt::DES BlockCipher object, using $key, where $key is a key of keysize() bytes.

my $cipher = Crypt::DES->new($key);
my $ciphertext = $cipher->encrypt($plaintext);

This function encrypts $plaintext and returns the $ciphertext where $plaintext and $ciphertext should be of blocksize() bytes.

my $cipher = Crypt::DES->new($key);
my $plaintext = $cipher->decrypt($ciphertext);

This function decrypts $ciphertext and returns the $plaintext where $plaintext and $ciphertext should be of blocksize() bytes.

This module is not deprecated as there may still be a reason to encrypt and decrypt using DES. However, DES is known to be weak. In 2026 a standard laptop can brute-force a DES key in a few days. DO NOT use DES (or this module) with any expectation of security.

my $key = pack("H16", "0123456789ABCDEF");
my $cipher = Crypt::DES->new($key);
my $ciphertext = $cipher->encrypt("plaintex");  # NB - 8 bytes
print unpack("H16", $ciphertext), "\n";
my $plaintext = $cipher->decrypt($ciphertext);
print $plaintext, "\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. CryptX (Crypt::Cipher::AES) is recommended if you want to replace Crypt::DES in a Crypt::CBC use case. Otherwise, replacing it with something like Crypt::AuthEnc::GCM would be recommended.

Crypt::AuthEnc::GCM Crypt::Blowfish Crypt::IDEA

Bruce Schneier, 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>.

Timothy Legge <timlegge@gmail.com> started maintaining this module as of version 2.08.

2026-08-11 perl v5.42.2