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package Crypt::Cipher;
use strict;
use warnings;
our $VERSION = '0.056';
use Carp;
$Carp::Internal{(__PACKAGE__)}++;
use CryptX;
### the following methods/functions are implemented in XS:
# - _new
# - DESTROY
# - _keysize
# - _max_keysize
# - _min_keysize
# - _blocksize
# - _default_rounds
# - encrypt
# - decrypt
#functions, not methods:
# - _block_length_by_name
# - _min_key_length_by_name
# - _max_key_length_by_name
# - _default_rounds_by_name
sub _trans_cipher_name {
my $name = shift || "";
my %trans = (
DES_EDE => '3des',
SAFERP => 'safer+',
SAFER_K128 => 'safer-k128',
SAFER_K64 => 'safer-k64',
SAFER_SK128 => 'safer-sk128',
SAFER_SK64 => 'safer-sk64',
);
$name =~ s/^Crypt::Cipher:://;
return $trans{uc($name)} if defined $trans{uc($name)};
return lc($name);
}
### METHODS
sub new {
my $pkg = shift;
my $cipher_name = $pkg eq __PACKAGE__ ? _trans_cipher_name(shift) : _trans_cipher_name($pkg);
local $SIG{__DIE__} = \&CryptX::_croak;
return _new($cipher_name, @_);
}
sub blocksize {
my $self = shift;
return $self->_blocksize if ref($self);
$self = _trans_cipher_name(shift) if $self eq __PACKAGE__;
local $SIG{__DIE__} = \&CryptX::_croak;
return _block_length_by_name(_trans_cipher_name($self));
}
sub max_keysize
{
my $self = shift;
return unless defined $self;
return $self->_max_keysize if ref($self);
$self = _trans_cipher_name(shift) if $self eq __PACKAGE__;
local $SIG{__DIE__} = \&CryptX::_croak;
return _max_key_length_by_name(_trans_cipher_name($self));
}
sub min_keysize {
my $self = shift;
return unless defined $self;
return $self->_min_keysize if ref($self);
$self = _trans_cipher_name(shift) if $self eq __PACKAGE__;
local $SIG{__DIE__} = \&CryptX::_croak;
return _min_key_length_by_name(_trans_cipher_name($self));
}
sub keysize {
goto &max_keysize;
}
sub default_rounds {
my $self = shift;
return unless defined $self;
return $self->_default_rounds if ref($self);
$self = _trans_cipher_name(shift) if $self eq __PACKAGE__;
local $SIG{__DIE__} = \&CryptX::_croak;
return _default_rounds_by_name(_trans_cipher_name($self));
}
sub CLONE_SKIP { 1 } # prevent cloning
1;
=pod
=head1 NAME
Crypt::Cipher - Generic interface to cipher functions
=head1 SYNOPSIS
#### example 1 (encrypting single block)
use Crypt::Cipher;
my $key = '...'; # length has to be valid key size for this cipher
my $c = Crypt::Cipher->new('AES', $key);
my $blocksize = $c->blocksize;
my $ciphertext = $c->encrypt('plain text block'); #encrypt 1 block
my $plaintext = $c->decrypt($ciphertext); #decrypt 1 block
### example 2 (using CBC mode)
use Crypt::Mode::CBC;
my $key = '...'; # length has to be valid key size for this cipher
my $iv = '...'; # 16 bytes
my $cbc = Crypt::Mode::CBC->new('AES');
my $ciphertext = $cbc->encrypt("secret data", $key, $iv);
#### example 3 (compatibility with Crypt::CBC)
use Crypt::CBC;
use Crypt::Cipher;
my $key = '...'; # length has to be valid key size for this cipher
my $iv = '...'; # 16 bytes
my $cipher = Crypt::Cipher('AES', $key);
my $cbc = Crypt::CBC->new( -cipher=>$cipher, -iv=>$iv );
my $ciphertext = $cbc->encrypt("secret data");
=head1 DESCRIPTION
Provides an interface to various symmetric cipher algorithms.
B<BEWARE:> This module implements just elementary "one-block-(en|de)cryption" operation - if you want to
encrypt/decrypt generic data you have to use some of the cipher block modes - check for example
L<Crypt::Mode::CBC|Crypt::Mode::CBC>, L<Crypt::Mode::CTR|Crypt::Mode::CTR> or L<Crypt::CBC|Crypt::CBC> (which will be slower).
=head1 METHODS
=head2 new
Constructor, returns a reference to the cipher object.
## basic scenario
$d = Crypt::Cipher->new($name, $key);
# $name = one of 'AES', 'Anubis', 'Blowfish', 'CAST5', 'Camellia', 'DES', 'DES_EDE',
# 'KASUMI', 'Khazad', 'MULTI2', 'Noekeon', 'RC2', 'RC5', 'RC6',
# 'SAFERP', 'SAFER_K128', 'SAFER_K64', 'SAFER_SK128', 'SAFER_SK64',
# 'SEED', 'Skipjack', 'Twofish', 'XTEA', 'IDEA', 'Serpent'
# simply any <NAME> for which there exists Crypt::Cipher::<NAME>
# $key = binary key (keysize should comply with selected cipher requirements)
## some of the ciphers (e.g. MULTI2, RC5, SAFER) allow one to set number of rounds
$d = Crypt::Cipher->new('MULTI2', $key, $rounds);
# $rounds = positive integer (should comply with selected cipher requirements)
=head2 encrypt
Encrypts $plaintext and returns the $ciphertext where $plaintext and $ciphertext should be of B<blocksize> bytes.
$ciphertext = $d->encrypt($plaintext);
=head2 decrypt
Decrypts $ciphertext and returns the $plaintext where $plaintext and $ciphertext should be of B<blocksize> bytes.
$plaintext = $d->encrypt($ciphertext);
=head2 keysize
Just an alias for B<max_keysize> (needed for L<Crypt::CBC|Crypt::CBC> compatibility).
=head2 max_keysize
Returns the maximal allowed key size (in bytes) for given cipher.
$d->max_keysize;
#or
Crypt::Cipher->max_keysize('AES');
#or
Crypt::Cipher::max_keysize('AES');
=head2 min_keysize
Returns the minimal allowed key size (in bytes) for given cipher.
$d->min_keysize;
#or
Crypt::Cipher->min_keysize('AES');
#or
Crypt::Cipher::min_keysize('AES');
=head2 blocksize
Returns block size (in bytes) for given cipher.
$d->blocksize;
#or
Crypt::Cipher->blocksize('AES');
#or
Crypt::Cipher::blocksize('AES');
=head2 default_rounds
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().
$d->default_rounds;
#or
Crypt::Cipher->default_rounds('AES');
#or
Crypt::Cipher::default_rounds('AES');
=head1 SEE ALSO
=over
=item * L<CryptX|CryptX>
=item * Check subclasses like L<Crypt::Cipher::AES|Crypt::Cipher::AES>, L<Crypt::Cipher::Blowfish|Crypt::Cipher::Blowfish>, ...
=back
=cut
|
