Ahmad Fatoum
and 1 contributors

NAME

Crypt::XTEA::LE - Implementation of the eXtended Tiny Encryption Algorithm with little-endian support

VERSION

version 0.0107

SYNOPSIS

   use Crypt::XTEA:LE;
   use Crypt::CBC;

   my $xtea = Crypt::XTEA:LE->new( $key, 32, little_endian => 1 );
   my $cbc = Crypt::CBC->new( -cipher => $xtea );

   my $text = 'The quick brown fox jumps over the lazy dog.';
   my $cipher_text = $cbc->encrypt( $text );

   my $plain_text = $cbc->decrypt( $cipher_text );

DESCRIPTION

In cryptography, XTEA (eXtended TEA) is a block cipher designed to correct weaknesses in TEA. The cipher's designers were David Wheeler and Roger Needham of the Cambridge Computer Laboratory, and the algorithm was presented in an unpublished technical report in 1997 (Needham and Wheeler, 1997). It is not subject to any patents.

Like TEA, XTEA is a 64-bit block Feistel cipher with a 128-bit key and a suggested 64 Feistel rounds (i.e 32 cycles). Crypt::XTEA::LE, uses the recommended value of 32 by default.

This module implements XTEA encryption. It supports the Crypt::CBC interface, with the following functions.

METHODS

keysize

Returns the maximum XTEA key size, 16 bytes.

blocksize

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

new

    my $xtea = Crypt::XTEA::LE->new( $key, $rounds, little_endian => 0 );

This creates a new Crypt::XTEA::LE object with the specified key. The optional rounds parameter specifies the number of rounds of encryption to perform, and defaults to 32. If the key is provided as a scalar string, it is split to a series of 4x big-endian 32-bit integers. If little-endian order is required instead, the optional little_endian key can be set to 1.

encrypt

    $cipher_text = $xtea->encrypt($plain_text);

Encrypts blocksize() bytes of $plain_text and returns the corresponding ciphertext. By default, the block is interpreted as 2x big-endian 32-bit integers. if little_endian => 1 was specified during new(), the block will be split into two little-endian integers instead.

decrypt

    $plain_text = $xtea->decrypt($cipher_text);

Decrypts blocksize() bytes of $cipher_text and returns the corresponding plaintext. By default, the block is interpreted as 2x big-endian 32-bit integers. if little_endian => 1 was specified during new(), the block will be split into two little-endian integers instead.

SEE ALSO

Based on Crypt::XTEA

Crypt::CBC

Crypt::XTEA_PP

AUTHOR

Kars Wang <jahiy@cpan.org> Ahmad Fatoum <athreef@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2015 by Kars Wang.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.