/ 
CryptX-0.026_08
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/ Crypt::AuthEnc::OCB

NAME

Crypt::AuthEnc::OCB - Authenticated encryption in OCBv3 mode

SYNOPSIS

### OO interface
use Crypt::AuthEnc::OCB;

my $ae = Crypt::AuthEnc::OCB->new("AES", $key, $nonce);
$ae->adata_add('aad1');
$ae->adata_add('aad2');
$ct = $ae->encrypt_add($data1);
$ct = $ae->encrypt_add($data2);
$ct = $ae->encrypt_add($data3);
$ct = $ae->encrypt_last('rest of data');
($ct,$tag) = $ae->encrypt_done();

my $ae = Crypt::AuthEnc::OCB->new("AES", $key, $nonce);
$ae->adata_add('aad1');
$ae->adata_add('aad2');
$pt = $ae->decrypt_add($data1);
$pt = $ae->decrypt_add($data2);
$pt = $ae->decrypt_add($data3);
$pt = $ae->decrypt_last('rest of data');
($pt,$tag) = $ae->decrypt_done();

### functional interface
use Crypt::AuthEnc::OCB qw(ocb_encrypt_authenticate ocb_decrypt_verify);

my ($ciphertext, $tag) = ocb_encrypt_authenticate('AES', $key, $nonce, $aad, $plaintext);
my $plaintext = ocb_decrypt_verify('AES', $key, $nonce, $aad, $ciphertext, $tag);

DESCRIPTION

This module implements OCB version 3 according http://datatracker.ietf.org/doc/draft-irtf-cfrg-ocb/

EXPORT

Nothing is exported by default.

You can export selected functions:

use Crypt::AuthEnc::OCB qw(ocb_encrypt_authenticate ocb_decrypt_verify);

FUNCTIONS

ocb_encrypt_authenticate

my ($ciphertext, $tag) = ocb_encrypt_authenticate($cipher, $key, $nonce, $aad, $plaintext);

# $cipher .. 'AES' or name of any other cipher with 16-byte block len
# $key ..... AES key of proper length (128/192/256bits)
# $nonce ... unique nonce/salt (no need to keep it secret)
# $aad ..... meta-data you want to send with the message but not have encrypted

ocb_decrypt_verify

my $plaintext = ocb_decrypt_verify($cipher, $key, $nonce, $aad, $ciphertext, $tag);

# on error returns undef

METHODS

new

my $ae = Crypt::AuthEnc::OCB->new($cipher, $key, $nonce);

# $cipher .. 'AES' or name of any other cipher with 16-byte block len
# $key ..... AES key of proper length (128/192/256bits)
# $nonce ... unique nonce/salt (no need to keep it secret)

adata_add

$ae->adata_add($aad);                          #can be called multiple times

encrypt_add

$ciphertext = $ae->encrypt_add($data);         #can be called multiple times

#BEWARE: size of $data has to be multiple of blocklen (16 for AES)

encrypt_last

$ciphertext = $ae->encrypt_last($data);

encrypt_done

$tag = $ae->encrypt_done();

decrypt_add

$plaintext = $ae->decrypt_add($ciphertext);    #can be called multiple times

#BEWARE: size of $ciphertext has to be multiple of blocklen (16 for AES)

encrypt_last

$plaintext = $ae->decrypt_last($data);

decrypt_done

my $result = $ae->decrypt_done($tag);  # returns 1 (success) or 0 (failure)
#or
my $tag = $ae->decrypt_done;           # returns $tag value

clone

my $ae_new = $ae->clone;

SEE ALSO