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CryptX-0.026_15
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/ Crypt::AuthEnc::EAX

NAME

Crypt::AuthEnc::EAX - Authenticated encryption in EAX mode

SYNOPSIS

### example 1
use Crypt::AuthEnc::EAX;

# encrypt + authenticate
my $ae = Crypt::AuthEnc::EAX->new("AES", $key, $nonce);
$ae->header_add('headerdata part1');
$ae->header_add('headerdata part2');
$ct = $ae->encrypt_add('data1');
$ct = $ae->encrypt_add('data2');
$ct = $ae->encrypt_add('data3');
$tag = $ae->encrypt_done();

# decrypt + verify
my $ae = Crypt::AuthEnc::EAX->new("AES", $key, $nonce);
$ae->header_add('headerdata part1');
$ae->header_add('headerdata part2');
$pt = $ae->decrypt_add('ciphertext1');
$pt = $ae->decrypt_add('ciphertext2');
$pt = $ae->decrypt_add('ciphertext3');

my $result = $ae->decrypt_done($tag);
#or
my $tag_dec = $ae->decrypt_done;
die "TAG mismatch" unless $tag eq $tag_dec;

### example 2
use Crypt::AuthEnc::EAX qw(eax_encrypt_authenticate eax_decrypt_verify);

my ($ciphertext, $tag) = eax_encrypt_authenticate('AES', $key, $nonce, $header, $plaintext);
my $plaintext = eax_decrypt_verify('AES', $key, $nonce, $header, $ciphertext, $tag);

DESCRIPTION

EAX is a mode that requires a cipher, CTR and OMAC support and provides encryption and authentication. It is initialized with a random nonce that can be shared publicly, a header which can be fixed and public, and a random secret symmetric key.

EXPORT

Nothing is exported by default.

You can export selected functions:

use Crypt::AuthEnc::EAX qw(eax_encrypt_authenticate eax_decrypt_verify);

FUNCTIONS

eax_encrypt_authenticate

my ($ciphertext, $tag) = eax_encrypt_authenticate($cipher, $key, $nonce, $header, $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)
# $header .. meta-data you want to send with the message but not have encrypted

eax_decrypt_verify

my $plaintext = eax_decrypt_verify($cipher, $key, $nonce, $header, $ciphertext, $tag);

# on error returns undef

METHODS

new

my $ae = Crypt::AuthEnc::EAX->new($cipher, $key, $nonce);
#or
my $ae = Crypt::AuthEnc::EAX->new($cipher, $key, $nonce, $header);

# $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)
# $header .. meta-data you want to send with the message but not have encrypted

header_add

$ae->header_add($header_data);                 #can be called multiple times

encrypt_add

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

encrypt_done

$tag = $ae->encrypt_done();

decrypt_add

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

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