Blowfish(3pm) User Contributed Perl Documentation Blowfish(3pm)
NAME
Crypt::Blowfish - Perl Blowfish encryption module
SYNOPSIS
use Crypt::Blowfish;
my $cipher = new Crypt::Blowfish $key;
my $ciphertext = $cipher->encrypt($plaintext);
my $plaintext = $cipher->decrypt($ciphertext);
You probably want to use this in conjunction with
a block chaining module like Crypt::CBC.
DESCRIPTION
Blowfish is capable of strong encryption and can use key sizes up to 56 bytes (a 448 bit key). You're encouraged to take advantage of the
full key size to ensure the strongest encryption possible from this module.
Crypt::Blowfish has the following methods:
blocksize()
keysize()
encrypt()
decrypt()
FUNCTIONS
blocksize
Returns the size (in bytes) of the block cipher.
Crypt::Blowfish doesn't return a key size due to its ability to use variable-length keys. More accurately, it shouldn't, but it does
anyway to play nicely with others.
new
my $cipher = new Crypt::Blowfish $key;
This creates a new Crypt::Blowfish BlockCipher object, using $key, where $key is a key of "keysize()" bytes (minimum of eight bytes).
encrypt
my $cipher = new Crypt::Blowfish $key;
my $ciphertext = $cipher->encrypt($plaintext);
This function encrypts $plaintext and returns the $ciphertext where $plaintext and $ciphertext must be of "blocksize()" bytes. (hint:
Blowfish is an 8 byte block cipher)
decrypt
my $cipher = new Crypt::Blowfish $key;
my $plaintext = $cipher->decrypt($ciphertext);
This function decrypts $ciphertext and returns the $plaintext where $plaintext and $ciphertext must be of "blocksize()" bytes. (hint:
see previous hint)
EXAMPLE
my $key = pack("H16", "0123456789ABCDEF"); # min. 8 bytes
my $cipher = new Crypt::Blowfish $key;
my $ciphertext = $cipher->encrypt("plaintex"); # SEE NOTES
print unpack("H16", $ciphertext), "
";
PLATFORMS
Please see the README document for platforms and performance
tests.
NOTES
The module is capable of being used with Crypt::CBC. You're encouraged to read the perldoc for Crypt::CBC if you intend to use this module
for Cipher Block Chaining modes. In fact, if you have any intentions of encrypting more than eight bytes of data with this, or any other
block cipher, you're going to need some type of block chaining help. Crypt::CBC tends to be very good at this. If you're not going to
encrypt more than eight bytes, your data must be exactly eight bytes long. If need be, do your own padding. " " as a null byte is
perfectly valid to use for this.
SEE ALSO
Crypt::CBC, Crypt::DES, Crypt::IDEA
Bruce Schneier, Applied Cryptography, 1995, Second Edition, published by John Wiley & Sons, Inc.
COPYRIGHT
The implementation of the Blowfish algorithm was developed by, and is copyright of, A.M. Kuchling.
Other parts of the perl extension and module are copyright of Systemics Ltd ( http://www.systemics.com/ ).
Code revisions, updates, and standalone release are copyright 1999-2010 W3Works, LLC.
AUTHOR
Original algorithm, Bruce Shneier. Original implementation, A.M. Kuchling. Original Perl implementation, Systemics Ltd. Current
maintenance by W3Works, LLC.
Current revision and maintainer: Dave Paris <amused@pobox.com>
perl v5.14.2 2010-03-04 Blowfish(3pm)