CAST5(3pm)						User Contributed Perl Documentation						CAST5(3pm)

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), "
";

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

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.

perl v5.14.2							    2006-07-01								CAST5(3pm)