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CryptX-0.087_002
⭐ Starred 36 / Crypt::Mac::OMAC
Security Advisories (2)
CVE-2026-41564 (2026-04-23)

CryptX versions before 0.088 for Perl do not reseed the Crypt::PK PRNG state after forking. The Crypt::PK::RSA, Crypt::PK::DSA, Crypt::PK::DH, Crypt::PK::ECC, Crypt::PK::Ed25519 and Crypt::PK::X25519 modules seed a per-object PRNG state in their constructors and reuse it without fork detection. A Crypt::PK::* object created before `fork()` shares byte-identical PRNG state with every child process, and any randomized operation they perform can produce identical output, including key generation. Two ECDSA or DSA signatures from different processes are enough to recover the signing private key through nonce-reuse key recovery. This affects preforking services such as the Starman web server, where a Crypt::PK::* object loaded at startup is inherited by every worker process.

CVE-2026-41565 (2026-05-28)

CryptX versions before 0.088_001 for Perl have a stack buffer overflow in four AEAD decrypt_verify helpers. The gcm_decrypt_verify, ccm_decrypt_verify, chacha20poly1305_decrypt_verify and eax_decrypt_verify XS routines copied the caller-supplied authentication tag into a fixed 144-byte stack buffer (MAXBLOCKSIZE) without checking the supplied length. A longer tag overwrites the stack past the buffer. Version 0.088 added the clamp to gcm_decrypt_verify, and 0.088_001 added it to the other three. Any caller of an affected helper that forwards an attacker-controlled tag longer than the buffer can trigger the overflow.

NAME

Crypt::Mac::OMAC - Message authentication code OMAC

SYNOPSIS

### Functional interface:
use Crypt::Mac::OMAC qw( omac omac_hex );

# calculate MAC from string/buffer
$omac_raw  = omac($cipher_name, $key, 'data buffer');
$omac_hex  = omac_hex($cipher_name, $key, 'data buffer');
$omac_b64  = omac_b64($cipher_name, $key, 'data buffer');
$omac_b64u = omac_b64u($cipher_name, $key, 'data buffer');

### OO interface:
use Crypt::Mac::OMAC;

$d = Crypt::Mac::OMAC->new($cipher_name, $key);
$d->add('any data');
$d->addfile('filename.dat');
$d->addfile(*FILEHANDLE);
$result_raw  = $d->mac;     # raw bytes
$result_hex  = $d->hexmac;  # hexadecimal form
$result_b64  = $d->b64mac;  # Base64 form
$result_b64u = $d->b64umac; # Base64 URL Safe form

DESCRIPTION

Provides an interface to the OMAC message authentication code (MAC) algorithm.

EXPORT

Nothing is exported by default.

You can export selected functions:

use Crypt::Mac::OMAC qw(omac omac_hex );

Or all of them at once:

use Crypt::Mac::OMAC ':all';

FUNCTIONS

omac

Logically joins all arguments into a single string, and returns its OMAC message authentication code encoded as a binary string.

$omac_raw = omac($cipher_name, $key, 'data buffer');
#or
$omac_raw = omac($cipher_name, $key, 'any data', 'more data', 'even more data');

omac_hex

Logically joins all arguments into a single string, and returns its OMAC message authentication code encoded as a hexadecimal string.

$omac_hex = omac_hex($cipher_name, $key, 'data buffer');
#or
$omac_hex = omac_hex($cipher_name, $key, 'any data', 'more data', 'even more data');

omac_b64

Logically joins all arguments into a single string, and returns its OMAC message authentication code encoded as a Base64 string.

$omac_b64 = omac_b64($cipher_name, $key, 'data buffer');
#or
$omac_b64 = omac_b64($cipher_name, $key, 'any data', 'more data', 'even more data');

omac_b64u

Logically joins all arguments into a single string, and returns its OMAC message authentication code encoded as a Base64 URL Safe string (see RFC 4648 section 5).

$omac_b64url = omac_b64u($cipher_name, $key, 'data buffer');
#or
$omac_b64url = omac_b64u($cipher_name, $key, 'any data', 'more data', 'even more data');

METHODS

new

$d = Crypt::Mac::OMAC->new($cipher_name, $key);

clone

$d->clone();

reset

$d->reset();

add

$d->add('any data');
#or
$d->add('any data', 'more data', 'even more data');

addfile

$d->addfile('filename.dat');
#or
$d->addfile(*FILEHANDLE);

mac

$result_raw = $d->mac();

hexmac

$result_hex = $d->hexmac();

b64mac

$result_b64 = $d->b64mac();

b64umac

$result_b64url = $d->b64umac();

SEE ALSO