/ 
CryptX-0.087_002
⭐ Starred 36 / Crypt::AuthEnc::ChaCha20Poly1305
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::AuthEnc::ChaCha20Poly1305 - Authenticated encryption in ChaCha20-Poly1305 mode

SYNOPSIS

### OO interface
use Crypt::AuthEnc::ChaCha20Poly1305;

# encrypt and authenticate
my $ae = Crypt::AuthEnc::ChaCha20Poly1305->new($key, $iv);
$ae->adata_add('additional_authenticated_data1');
$ae->adata_add('additional_authenticated_data2');
my $ct = $ae->encrypt_add('data1');
$ct .= $ae->encrypt_add('data2');
$ct .= $ae->encrypt_add('data3');
my $tag = $ae->encrypt_done();

# decrypt and verify
my $ae = Crypt::AuthEnc::ChaCha20Poly1305->new($key, $iv);
$ae->adata_add('additional_authenticated_data1');
$ae->adata_add('additional_authenticated_data2');
my $pt = $ae->decrypt_add('ciphertext1');
$pt .= $ae->decrypt_add('ciphertext2');
$pt .= $ae->decrypt_add('ciphertext3');
my $tag = $ae->decrypt_done();
die "decrypt failed" unless $tag eq $expected_tag;

#or
my $result = $ae->decrypt_done($expected_tag); # 0 or 1

### functional interface
use Crypt::AuthEnc::ChaCha20Poly1305 qw(chacha20poly1305_encrypt_authenticate chacha20poly1305_decrypt_verify);

my ($ciphertext, $tag) = chacha20poly1305_encrypt_authenticate($key, $iv, $adata, $plaintext);
my $plaintext = chacha20poly1305_decrypt_verify($key, $iv, $adata, $ciphertext, $tag);

DESCRIPTION

Provides encryption and authentication based on ChaCha20 + Poly1305 as defined in RFC 7539 - https://tools.ietf.org/html/rfc7539

EXPORT

Nothing is exported by default.

You can export selected functions:

use Crypt::AuthEnc::ChaCha20Poly1305 qw(chacha20poly1305_encrypt_authenticate chacha20poly1305_decrypt_verify);

FUNCTIONS

chacha20poly1305_encrypt_authenticate

my ($ciphertext, $tag) = chacha20poly1305_encrypt_authenticate($key, $iv, $adata, $plaintext);

# $key ..... key of proper length (128 or 256 bits / 16 or 32 bytes)
# $iv ...... initialization vector (64 or 96 bits / 8 or 12 bytes)
# $adata ... additional authenticated data (optional)

chacha20poly1305_decrypt_verify

my $plaintext = chacha20poly1305_decrypt_verify($key, $iv, $adata, $ciphertext, $tag);
# on error returns undef

METHODS

new

my $ae = Crypt::AuthEnc::ChaCha20Poly1305->new($key, $iv);

# $key ..... encryption key of proper length (128 or 256 bits / 16 or 32 bytes)
# $iv ...... initialization vector (64 or 96 bits / 8 or 12 bytes)

adata_add

Add additional authenticated data. Can be called before the first encrypt_add or decrypt_add;

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

encrypt_add

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

encrypt_done

$tag = $ae->encrypt_done();                    # returns $tag value

decrypt_add

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

decrypt_done

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

set_iv

my $ae = Crypt::AuthEnc::ChaCha20Poly1305->new($key)->set_iv($iv);
# $iv ...... initialization vector (64 or 96 bits / 8 or 12 bytes)

set_iv_rfc7905

See https://tools.ietf.org/html/rfc7905

my $ae = Crypt::AuthEnc::ChaCha20Poly1305->new($key)->set_iv_rfc7905($iv, $seqnum);
# $iv ...... initialization vector (96 bits / 12 bytes)
# $seqnum .. 64bit integer (sequence number)

clone

my $ae_new = $ae->clone;

SEE ALSO