NAME

Crypt::OpenSSL::AES - A Perl wrapper around OpenSSL's AES library

SYNOPSIS

     use Crypt::OpenSSL::AES;
     my $cipher = Crypt::OpenSSL::AES->new($key);
     or
     # Pick better keys and iv...
     my $key = pack("H*", substr(sha512_256_hex(rand(1000)), 0, ($ks/4)));
     my $iv  = pack("H*", substr(sha512_256_hex(rand(1000)), 0, 32));
     my $cipher = Crypt::OpenSSL::AES->new(
                                            $key,
                                            {
                                                cipher => 'AES-256-CBC',
                                                iv      => $iv, (16-bytes for supported ciphers)
                                                padding => 1, (0 - no padding, 1 - padding)
                                            }
                                        );
     $encrypted = $cipher->encrypt($plaintext);
     $decrypted = $cipher->decrypt($encrypted);

DESCRIPTION

This module implements a wrapper around OpenSSL. Specifically, it wraps the methods related to the US Government's Advanced Encryption Standard (the Rijndael algorithm). The original version supports only AES ECB (electronic codebook mode encryption).

This module is compatible with Crypt::CBC (and likely other modules that utilize a block cipher to make a stream cipher).

This module is an alternative to the implementation provided by Crypt::Rijndael which implements AES itself. In contrast, this module is simply a wrapper around the OpenSSL library.

As of version 0.09 additional AES ciphers are supported. Those are:

Block Ciphers: The blocksize is 16 bytes and must be padded if not a multiple of the blocksize.

AES-128-ECB, AES-192-ECB and AES-256-ECB (no IV): Supports padding
AES-128-CBC, AES-192-CBC and AES-256-CBC: Supports padding and iv

Stream Ciphers: The blocksize is 1 byte. OpenSSL does not pad even if padding is set (the default).

AES-128-CFB, AES-192-CFB and AES-256-CFB: Supports iv
AES-128-CTR, AES-192-CTR and AES-256-CTR: Supports iv
AES-128-OFB, AES-192-OFB and AES-256-OFB: Supports iv

new()

For compatibility with old versions you can simply pass the key to the new constructor.

    # The default cipher is AES-ECB based on the key size
    my $cipher = Crypt::OpenSSL::AES->new($key);
    or
    # the keysize must match the cipher size
    # 16-bytes (128-bits) AES-128-xxx
    # 24-bytes (192-bits) AES-192-xxx
    # 32-bytes (256-bits) AES-256-xxx
    my $cipher = Crypt::OpenSSL::AES->new($key,
                    {
                        cipher  => 'AES-256-CBC',
                        iv      => $iv, (16-bytes for supported ciphers)
                        padding => 1, (0 - no padding, 1 - padding)
                    });
    # cipher
    #   AES-128-ECB, AES-192-ECB and AES-256-ECB (no IV)
    #   AES-128-CBC, AES-192-CBC and AES-256-CBC
    #   AES-128-CFB, AES-192-CFB and AES-256-CFB
    #   AES-128-CTR, AES-192-CTR and AES-256-CTR
    #   AES-128-OFB, AES-192-OFB and AES-256-OFB
    #
    # iv - 16-byte random data
    #
    # padding
    #   0 - no padding
    #   1 - padding

$cipher->encrypt($data)

Encrypt data. For Block Ciphers (ECB and CBC) the size of $data must be exactly "blocksize" in length (16 bytes) or padding must be enabled in the new constructor, otherwise this function will croak.

For Stream ciphers (CFB, CTR or OFB) the block size is considered to be 1 byte and no padding is required.

Crypt::CBC is no longer required to encrypt/decrypt data of arbitrary lengths.

$cipher->decrypt($data)

Decrypts data. For Block Ciphers (ECB and CBC) the size of $data must be exactly "blocksize" in length (16 bytes) or padding must be enabled in the new constructor, otherwise this function will croak.

For Stream ciphers (CFB, CTR or OFB) the block size is considered to be 1 byte and no padding is required.

Crypt::CBC is no longer required to encrypt/decrypt data of arbitrary lengths.

keysize

This method is used by Crypt::CBC to verify the key length. This module actually supports key lengths of 16, 24, and 32 bytes, but this method always returns 32 for Crypt::CBC's sake.

blocksize

This method is used by Crypt::CBC to check the block size. The blocksize for AES is always 16 bytes.

USE WITH CRYPT::CBC

As padding is now supported for the CBC cipher, Crypt::CBC is no longer required but supported for backward compatibility.

        use Crypt::CBC;
        my $plaintext = "This is a test!!";
        my $password = "qwerty123";
        my $cipher = Crypt::CBC->new(
                -key    => $password,
                -cipher => "Crypt::OpenSSL::AES",
                -pbkdf  => 'pbkdf2',
        );
        my $encrypted = $cipher->encrypt($plaintext);
        my $decrypted = $cipher->decrypt($encrypted);

BUGS

Need more (and better) test cases.

AUTHOR

Tolga Tarhan, <cpan at ttar dot org>

The US Government's Advanced Encryption Standard is the Rijndael Algorithm and was developed by Vincent Rijmen and Joan Daemen.

COPYRIGHT AND LICENSE

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.5 or, at your option, any later version of Perl 5 you may have available.