NAME

       Crypt::CAST5 - CAST5 block cipher

SYNOPSIS

           use Crypt::CBC;

           my $crypt = Crypt::CBC->new({
               key    => "secret key",
               cipher => "CAST5",
           });

           my $message = "All mimsy were the borogoves";
           my $ciphertext = $crypt->encrypt($message);
           print unpack("H*", $ciphertext), "\n";

           my $plaintext = $crypt->decrypt($ciphertext);
           print $plaintext, "\n";

DESCRIPTION

       This module provides an implementation of the CAST5 block cipher using compiled C code for
       increased speed. CAST5 is also known as CAST-128. It is a product of the CAST design
       procedure developed by C. Adams and S. Tavares.

       The CAST5 cipher is available royalty-free.

FUNCTIONS

   blocksize
       Returns the CAST5 block size, which is 8 bytes. This function exists so that Crypt::CAST5
       can work with Crypt::CBC.

   keysize
       Returns the maximum CAST5 key size, 16 bytes.

   new
           $cast5 = Crypt::CAST5->new($key);

       Create a new encryption object. If the optional key parameter is given, it will be passed
       to the init() function.

   init
           $cast5->init($key);

       Set or change the encryption key to be used. The key must be from 40 bits (5 bytes) to 128
       bits (16 bytes) in length. Note that if the key used is 80 bits or less, encryption and
       decryption will be somewhat faster.

       It is best for the key to be random binary data, not something printable like a password.
       A message digest function may be useful for converting a password to an encryption key;
       see Digest::SHA1 or Digest::MD5.  Note that Crypt::CBC runs the given "key" through MD5 to
       get the actual encryption key.

   encrypt
           $ciphertext = $cast5->encrypt($plaintext);

       Encrypt a block of plaintext using the current encryption key, and return the
       corresponding ciphertext. The input must be 8 bytes long, and the output has the same
       length. Note that the encryption is in ECB mode, which means that it encrypts each block
       independently. That can leave you vulnerable to dictionary attacks, so it is generally
       best to use some form of chaining between blocks; see Crypt::CBC.

   decrypt
           $plaintext = $cast5->decrypt($ciphertext);

       Decrypt the ciphertext and return the corresponding plaintext.

SEE ALSO

       RFC 2144, "The CAST-128 Encryption Algorithm", C. Adams, May 1997

       Crypt::CBC

AUTHOR

       Bob Mathews, <bobmathews@alumni.calpoly.edu>

COPYRIGHT AND LICENSE

       Copyright (C) 2002-2006 Bob Mathews

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