156 lines
4.1 KiB
Perl
156 lines
4.1 KiB
Perl
package Crypt::Cipher;
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use strict;
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use warnings;
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our $VERSION = '0.058_002';
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use Carp;
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$Carp::Internal{(__PACKAGE__)}++;
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use CryptX;
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### the following methods/functions are implemented in XS:
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# - new
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# - DESTROY
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# - blocksize
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# - decrypt
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# - default_rounds
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# - encrypt
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# - max_keysize
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# - min_keysize
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sub keysize { goto \&max_keysize; } # for Crypt::CBC compatibility
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sub CLONE_SKIP { 1 } # prevent cloning
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1;
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=pod
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=head1 NAME
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Crypt::Cipher - Generic interface to cipher functions
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=head1 SYNOPSIS
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#### example 1 (encrypting single block)
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use Crypt::Cipher;
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my $key = '...'; # length has to be valid key size for this cipher
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my $c = Crypt::Cipher->new('AES', $key);
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my $blocksize = $c->blocksize;
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my $ciphertext = $c->encrypt('plain text block'); #encrypt 1 block
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my $plaintext = $c->decrypt($ciphertext); #decrypt 1 block
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### example 2 (using CBC mode)
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use Crypt::Mode::CBC;
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my $key = '...'; # length has to be valid key size for this cipher
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my $iv = '...'; # 16 bytes
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my $cbc = Crypt::Mode::CBC->new('AES');
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my $ciphertext = $cbc->encrypt("secret data", $key, $iv);
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#### example 3 (compatibility with Crypt::CBC)
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use Crypt::CBC;
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use Crypt::Cipher;
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my $key = '...'; # length has to be valid key size for this cipher
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my $iv = '...'; # 16 bytes
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my $cipher = Crypt::Cipher('AES', $key);
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my $cbc = Crypt::CBC->new( -cipher=>$cipher, -iv=>$iv );
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my $ciphertext = $cbc->encrypt("secret data");
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=head1 DESCRIPTION
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Provides an interface to various symmetric cipher algorithms.
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B<BEWARE:> This module implements just elementary "one-block-(en|de)cryption" operation - if you want to
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encrypt/decrypt generic data you have to use some of the cipher block modes - check for example
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L<Crypt::Mode::CBC|Crypt::Mode::CBC>, L<Crypt::Mode::CTR|Crypt::Mode::CTR> or L<Crypt::CBC|Crypt::CBC> (which will be slower).
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=head1 METHODS
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=head2 new
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Constructor, returns a reference to the cipher object.
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## basic scenario
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$d = Crypt::Cipher->new($name, $key);
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# $name = one of 'AES', 'Anubis', 'Blowfish', 'CAST5', 'Camellia', 'DES', 'DES_EDE',
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# 'KASUMI', 'Khazad', 'MULTI2', 'Noekeon', 'RC2', 'RC5', 'RC6',
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# 'SAFERP', 'SAFER_K128', 'SAFER_K64', 'SAFER_SK128', 'SAFER_SK64',
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# 'SEED', 'Skipjack', 'Twofish', 'XTEA', 'IDEA', 'Serpent'
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# simply any <NAME> for which there exists Crypt::Cipher::<NAME>
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# $key = binary key (keysize should comply with selected cipher requirements)
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## some of the ciphers (e.g. MULTI2, RC5, SAFER) allow one to set number of rounds
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$d = Crypt::Cipher->new('MULTI2', $key, $rounds);
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# $rounds = positive integer (should comply with selected cipher requirements)
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=head2 encrypt
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Encrypts $plaintext and returns the $ciphertext where $plaintext and $ciphertext should be of B<blocksize> bytes.
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$ciphertext = $d->encrypt($plaintext);
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=head2 decrypt
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Decrypts $ciphertext and returns the $plaintext where $plaintext and $ciphertext should be of B<blocksize> bytes.
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$plaintext = $d->encrypt($ciphertext);
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=head2 keysize
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Just an alias for B<max_keysize> (needed for L<Crypt::CBC|Crypt::CBC> compatibility).
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=head2 max_keysize
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Returns the maximal allowed key size (in bytes) for given cipher.
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$d->max_keysize;
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#or
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Crypt::Cipher->max_keysize('AES');
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#or
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Crypt::Cipher::max_keysize('AES');
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=head2 min_keysize
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Returns the minimal allowed key size (in bytes) for given cipher.
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$d->min_keysize;
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#or
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Crypt::Cipher->min_keysize('AES');
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#or
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Crypt::Cipher::min_keysize('AES');
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=head2 blocksize
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Returns block size (in bytes) for given cipher.
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$d->blocksize;
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#or
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Crypt::Cipher->blocksize('AES');
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#or
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Crypt::Cipher::blocksize('AES');
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=head2 default_rounds
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Returns default number of rounds for given cipher. NOTE: only some ciphers (e.g. MULTI2, RC5, SAFER) allow one to set number of rounds via new().
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$d->default_rounds;
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#or
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Crypt::Cipher->default_rounds('AES');
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#or
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Crypt::Cipher::default_rounds('AES');
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=head1 SEE ALSO
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=over
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=item * L<CryptX|CryptX>
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=item * Check subclasses like L<Crypt::Cipher::AES|Crypt::Cipher::AES>, L<Crypt::Cipher::Blowfish|Crypt::Cipher::Blowfish>, ...
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=back
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=cut
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