NAME

       Crypt::Eksblowfish::Blowfish - Blowfish block cipher via Eksblowfish engine

SYNOPSIS

               use Crypt::Eksblowfish::Blowfish;

               $block_size = Crypt::Eksblowfish::Blowfish->blocksize;
               $key_size = Crypt::Eksblowfish::Blowfish->keysize;

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

               $block_size = $cipher->blocksize;
               $ciphertext = $cipher->encrypt($plaintext);
               $plaintext = $cipher->decrypt($ciphertext);

               $p_array = $cipher->p_array;
               $s_boxes = $cipher->s_boxes;
               if($cipher->is_weak) { ...

DESCRIPTION

       An object of this type encapsulates a keyed instance of the Blowfish block cipher, ready
       to encrypt and decrypt.

       Blowfish is a symmetric cipher algorithm designed by Bruce Schneier in 1993.  It operates
       on 64-bit blocks, and takes a variable-length key from 32 bits (4 octets) to 448 bits (56
       octets) in increments of 8 bits (1 octet).

       This implementation of Blowfish uses an encryption engine that was originally implemented
       in order to support Eksblowfish, which is a variant of Blowfish modified to make keying
       particularly expensive.  See Crypt::Eksblowfish for that variant; this class implements
       the original Blowfish.

CLASS METHODS

       Crypt::Eksblowfish::Blowfish->blocksize
           Returns 8, indicating the Blowfish block size of 8 octets.  This method may be called
           on either the class or an instance.

       Crypt::Eksblowfish::Blowfish->keysize
           Returns 0, indicating that the key size is variable.  This situation is handled
           specially by "Crypt::CBC".

CONSTRUCTOR

       Crypt::Eksblowfish::Blowfish->new(KEY)
           Performs key setup on a new instance of the Blowfish algorithm, returning the keyed
           state.  The KEY may be any length from 4 octets to 56 octets inclusive.

           You may occasionally come across an alleged Blowfish key that is outside this length
           range, and so is rejected by this constructor.  Blowfish can internally process a key
           of any octet length up to 72 octets, and some implementations don't enforce the
           official length restrictions.  If it is necessary for compatibility, a key of out-of-
           range length can be processed by Crypt::Eksblowfish::Uklblowfish.

METHODS

       $cipher->blocksize
           Returns 8, indicating the Blowfish block size of 8 octets.  This method may be called
           on either the class or an instance.

       $cipher->encrypt(PLAINTEXT)
           PLAINTEXT must be exactly eight octets.  The block is encrypted, and the ciphertext is
           returned.

       $cipher->decrypt(CIPHERTEXT)
           CIPHERTEXT must be exactly eight octets.  The block is decrypted, and the plaintext is
           returned.

       $cipher->p_array
       $cipher->s_boxes
           These methods extract the subkeys from the keyed cipher.  This is not required in
           ordinary operation.  See the superclass Crypt::Eksblowfish::Subkeyed for details.

       $cipher->is_weak
           This method checks whether the cipher has been keyed with a weak key.  It may be
           desired to avoid using weak keys.  See the superclass Crypt::Eksblowfish::Subkeyed for
           details.

SEE ALSO

       Crypt::Eksblowfish, Crypt::Eksblowfish::Subkeyed, Crypt::Eksblowfish::Uklblowfish,
       <http://www.schneier.com/blowfish.html>

AUTHOR

       Eksblowfish guts originally by Solar Designer (solar at openwall.com).

       Modifications and Perl interface by Andrew Main (Zefram) <zefram@fysh.org>.

COPYRIGHT

       Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Andrew Main (Zefram) <zefram@fysh.org>

       The original Eksblowfish code (in the form of crypt()) from which this module is derived
       is in the public domain.  It may be found at <http://www.openwall.com/crypt/>.

LICENSE

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