/ 
CryptX-0.020
⭐ Starred 36 / Crypt::PK::RSA
Security Advisories (6)
CVE-2025-40912 (2025-06-11)

CryptX for Perl before version 0.065 contains a dependency that may be susceptible to malformed unicode. CryptX embeds the tomcrypt library. The versions of that library in CryptX before 0.065 may be susceptible to CVE-2019-17362.

CVE-2025-40914 (2025-06-11)

Perl CryptX before version 0.087 contains a dependency that may be susceptible to an integer overflow. CryptX embeds a version of the libtommath library that is susceptible to an integer overflow associated with CVE-2023-36328.

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-2018-25099 (2018-10-26)

A user can pass anything as the tag into gcm_decrypt_verify() and it will return decrypted plaintext.

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.

CVE-2026-13758 (2026-06-29)

CryptX versions before 0.088_001 for Perl compare AEAD authentication tags in non-constant time in the streaming decrypt_done path. The decrypt_done($tag) form compares it against the computed tag with memNE (memcmp() != 0), which short-circuits on the first differing byte, so its run time depends on the number of matching leading bytes. This affects all five AEAD modes: GCM, CCM, ChaCha20Poly1305, EAX and OCB. The one-shot *_decrypt_verify helpers are unaffected; they verify the tag inside libtomcrypt with a constant-time comparison. The timing difference is a tag-verification oracle. An attacker who can submit many candidate tags for the same nonce, ciphertext and associated data while measuring the timing precisely enough may recover the expected tag byte by byte and forge a message that verifies.

NAME

Crypt::PK::RSA - Public key cryptography based on RSA

SYNOPSIS

### OO interface

#Encryption: Alice
my $pub = Crypt::PK::RSA->new('Bob_pub_rsa1.der');
my $ct = $pub->encrypt("secret message");
#
#Encryption: Bob (received ciphertext $ct)
my $priv = Crypt::PK::RSA->new('Bob_priv_rsa1.der');
my $pt = $priv->decrypt($ct);

#Signature: Alice
my $priv = Crypt::PK::RSA->new('Alice_priv_rsa1.der');
my $sig = $priv->sign_message($message);
#
#Signature: Bob (received $message + $sig)
my $pub = Crypt::PK::RSA->new('Alice_pub_rsa1.der');
$pub->verify_message($sig, $message) or die "ERROR";

#Key generation
my $pk = Crypt::PK::RSA->new();
$pk->generate_key(256, 65537);
my $private_der = $pk->export_key_der('private');
my $public_der = $pk->export_key_der('public');
my $private_pem = $pk->export_key_pem('private');
my $public_pem = $pk->export_key_pem('public');

### Functional interface

#Encryption: Alice
my $ct = rsa_encrypt('Bob_pub_rsa1.der', "secret message");
#Encryption: Bob (received ciphertext $ct)
my $pt = rsa_decrypt('Bob_priv_rsa1.der', $ct);

#Signature: Alice
my $sig = rsa_sign_message('Alice_priv_rsa1.der', $message);
#Signature: Bob (received $message + $sig)
rsa_verify_message('Alice_pub_rsa1.der', $sig, $message) or die "ERROR";

DESCRIPTION

The module provides a full featured RSA implementation.

METHODS

new

my $pk = Crypt::PK::RSA->new();
#or
my $pk = Crypt::PK::RSA->new($priv_or_pub_key_filename);
#or
my $pk = Crypt::PK::RSA->new(\$buffer_containing_priv_or_pub_key);

Support for password protected PEM keys

my $pk = Crypt::PK::RSA->new($priv_pem_key_filename, $password);
#or
my $pk = Crypt::PK::RSA->new(\$buffer_containing_priv_pem_key, $password);

generate_key

Uses Yarrow-based cryptographically strong random number generator seeded with random data taken from /dev/random (UNIX) or CryptGenRandom (Win32).

$pk->generate_key($size, $e);
# $size .. key size: 128-512 bytes (DEFAULT is 256)
# $e ..... exponent: 3, 17, 257 or 65537 (DEFAULT is 65537)

import_key

Loads private or public key in DER or PEM format.

$pk->import_key($priv_or_pub_key_filename);
#or
$pk->import_key(\$buffer_containing_priv_or_pub_key);

Support for password protected PEM keys

$pk->import_key($pem_filename, $password);
#or
$pk->import_key(\$buffer_containing_pem_key, $password);

export_key_der

my $private_der = $pk->export_key_der('private');
#or
my $public_der = $pk->export_key_der('public');

export_key_pem

my $private_pem = $pk->export_key_pem('private');
#or
my $public_pem = $pk->export_key_pem('public');
#or
my $public_pem = $pk->export_key_pem('public_x509');

With parameter 'public' uses header and footer lines:

-----BEGIN RSA PUBLIC KEY------
-----END RSA PUBLIC KEY------

With parameter 'public_x509' uses header and footer lines:

-----BEGIN PUBLIC KEY------
-----END PUBLIC KEY------

Support for password protected PEM keys

my $private_pem = $pk->export_key_pem('private', $password);
#or
my $private_pem = $pk->export_key_pem('private', $password, $cipher);

# supported ciphers: 'DES-CBC'
#                    'DES-EDE3-CBC'
#                    'SEED-CBC'
#                    'CAMELLIA-128-CBC'
#                    'CAMELLIA-192-CBC'
#                    'CAMELLIA-256-CBC'
#                    'AES-128-CBC'
#                    'AES-192-CBC'
#                    'AES-256-CBC' (DEFAULT)

encrypt

my $pk = Crypt::PK::RSA->new($pub_key_filename);
my $ct = $pk->encrypt($message);
#or
my $ct = $pk->encrypt($message, $padding);
#or
my $ct = $pk->encrypt($message, 'oaep', $hash_name, $lparam);

# $padding .................... 'oaep' (DEFAULT), 'v1.5' or 'none'
# $hash_name (only for oaep) .. 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $lparam (only for oaep) ..... DEFAULT is empty string

decrypt

my $pk = Crypt::PK::RSA->new($priv_key_filename);
my $pt = $pk->decrypt($ciphertext);
#or
my $pt = $pk->decrypt($ciphertext, $padding);
#or
my $pt = $pk->decrypt($ciphertext, 'oaep', $hash_name, $lparam);

# $padding .................... 'oaep' (DEFAULT), 'v1.5' or 'none'
# $hash_name (only for oaep) .. 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $lparam (only for oaep) ..... DEFAULT is empty string

sign_message

my $pk = Crypt::PK::RSA->new($priv_key_filename);
my $signature = $priv->sign_message($message);
#or
my $signature = $priv->sign_message($message, $hash_name);
#or
my $signature = $priv->sign_message($message, $hash_name, $padding);
#or
my $signature = $priv->sign_message($message, $hash_name, 'pss', $saltlen);

# $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $padding ................. 'pss' (DEFAULT) or 'v1.5'
# $saltlen (only for pss) .. DEFAULT is 12

verify_message

my $pk = Crypt::PK::RSA->new($pub_key_filename);
my $valid = $pub->verify_message($signature, $message);
#or
my $valid = $pub->verify_message($signature, $message, $hash_name);
#or
my $valid = $pub->verify_message($signature, $message, $hash_name, $padding);
#or
my $valid = $pub->verify_message($signature, $message, $hash_name, 'pss', $saltlen);

# $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $padding ................. 'pss' (DEFAULT) or 'v1.5'
# $saltlen (only for pss) .. DEFAULT is 12

sign_hash

my $pk = Crypt::PK::RSA->new($priv_key_filename);
my $signature = $priv->sign_hash($message_hash);
#or
my $signature = $priv->sign_hash($message_hash, $hash_name);
#or
my $signature = $priv->sign_hash($message_hash, $hash_name, $padding);
#or
my $signature = $priv->sign_hash($message_hash, $hash_name, 'pss', $saltlen);

# $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $padding ................. 'pss' (DEFAULT) or 'v1.5'
# $saltlen (only for pss) .. DEFAULT is 12

verify_hash

my $pk = Crypt::PK::RSA->new($pub_key_filename);
my $valid = $pub->verify_hash($signature, $message_hash);
#or
my $valid = $pub->verify_hash($signature, $message_hash, $hash_name);
#or
my $valid = $pub->verify_hash($signature, $message_hash, $hash_name, $padding);
#or
my $valid = $pub->verify_hash($signature, $message_hash, $hash_name, 'pss', $saltlen);

# $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $padding ................. 'pss' (DEFAULT) or 'v1.5'
# $saltlen (only for pss) .. DEFAULT is 12

is_private

my $rv = $pk->is_private;
# 1 .. private key loaded
# 0 .. public key loaded
# undef .. no key loaded

size

my $size = $pk->size;
# returns key size in bytes or undef if no key loaded

key2hash

my $hash = $pk->key2hash;

# returns hash like this (or undef if no key loaded):
{
  type => 1,   # integer: 1 .. private, 0 .. public
  size => 256, # integer: key size in bytes
  # all the rest are hex strings
  e  => "10001", #public exponent
  d  => "9ED5C3D3F866E06957CA0E9478A273C39BBDA4EEAC5B...", #private exponent
  N  => "D0A5CCCAE03DF9C2F5C4C8C0CE840D62CDE279990DC6...", #modulus
  p  => "D3EF0028FFAB508E2773C659E428A80FB0E9211346B4...", #p factor of N
  q  => "FC07E46B163CAB6A83B8E467D169534B2077DCDEECAE...", #q factor of N
  qP => "88C6D406F833DF73C8B734548E0385261AD51F4187CF...", #1/q mod p CRT param
  dP => "486F142FEF0A1F53269AC43D2EE4D263E2841B60DA36...", #d mod (p - 1) CRT param
  dQ => "4597284B2968B72C4212DB7E8F24360B987B80514DA9...", #d mod (q - 1) CRT param
}

FUNCTIONS

rsa_encrypt

RSA based encryption. See method "encrypt" below.

my $ct = rsa_encrypt($pub_key_filename, $message);
#or
my $ct = rsa_encrypt(\$buffer_containing_pub_key, $message);
#or
my $ct = rsa_encrypt($pub_key, $message, $padding);
#or
my $ct = rsa_encrypt($pub_key, $message, 'oaep', $hash_name, $lparam);

# $padding .................... 'oaep' (DEFAULT), 'v1.5' or 'none'
# $hash_name (only for oaep) .. 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $lparam (only for oaep) ..... DEFAULT is empty string

rsa_decrypt

RSA based decryption. See method "decrypt" below.

my $pt = rsa_decrypt($priv_key_filename, $ciphertext);
#or
my $pt = rsa_decrypt(\$buffer_containing_priv_key, $ciphertext);
#or
my $pt = rsa_decrypt($priv_key, $ciphertext, $padding);
#or
my $pt = rsa_decrypt($priv_key, $ciphertext, 'oaep', $hash_name, $lparam);

# $padding .................... 'oaep' (DEFAULT), 'v1.5' or 'none'
# $hash_name (only for oaep) .. 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $lparam (only for oaep) ..... DEFAULT is empty string

rsa_sign_message

Generate RSA signature. See method "sign_message" below.

my $sig = rsa_sign_message($priv_key_filename, $message);
#or
my $sig = rsa_sign_message(\$buffer_containing_priv_key, $message);
#or
my $sig = rsa_sign_message($priv_key, $message, $hash_name);
#or
my $sig = rsa_sign_message($priv_key, $message, $hash_name, $padding);
#or
my $sig = rsa_sign_message($priv_key, $message, $hash_name, 'pss', $saltlen);

# $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $padding ................. 'pss' (DEFAULT) or 'v1.5'
# $saltlen (only for pss) .. DEFAULT is 12

rsa_verify_message

Verify RSA signature. See method "verify_message" below.

rsa_verify_message($pub_key_filename, $signature, $message) or die "ERROR";
#or
rsa_verify_message(\$buffer_containing_pub_key, $signature, $message) or die "ERROR";
#or
rsa_verify_message($pub_key, $signature, $message, $hash_name) or die "ERROR";
#or
rsa_verify_message($pub_key, $signature, $message, $hash_name, $padding) or die "ERROR";
#or
rsa_verify_message($pub_key, $signature, $message, $hash_name, 'pss', $saltlen) or die "ERROR";

# $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $padding ................. 'pss' (DEFAULT) or 'v1.5'
# $saltlen (only for pss) .. DEFAULT is 12

rsa_sign_hash

Generate RSA signature. See method "sign_hash" below.

my $sig = rsa_sign_hash($priv_key_filename, $message_hash);
#or
my $sig = rsa_sign_hash(\$buffer_containing_priv_key, $message_hash);
#or
my $sig = rsa_sign_hash($priv_key, $message_hash, $hash_name);
#or
my $sig = rsa_sign_hash($priv_key, $message_hash, $hash_name, $padding);
#or
my $sig = rsa_sign_hash($priv_key, $message_hash, $hash_name, 'pss', $saltlen);

# $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $padding ................. 'pss' (DEFAULT) or 'v1.5'
# $saltlen (only for pss) .. DEFAULT is 12

rsa_verify_hash

Verify RSA signature. See method "verify_hash" below.

rsa_verify_hash($pub_key_filename, $signature, $message_hash) or die "ERROR";
#or
rsa_verify_hash(\$buffer_containing_pub_key, $signature, $message_hash) or die "ERROR";
#or
rsa_verify_hash($pub_key, $signature, $message_hash, $hash_name) or die "ERROR";
#or
rsa_verify_hash($pub_key, $signature, $message_hash, $hash_name, $padding) or die "ERROR";
#or
rsa_verify_hash($pub_key, $signature, $message_hash, $hash_name, 'pss', $saltlen) or die "ERROR";

# $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
# $padding ................. 'pss' (DEFAULT) or 'v1.5'
# $saltlen (only for pss) .. DEFAULT is 12

OpenSSL interoperability

### let's have:
# RSA private key in PEM format - rsakey.priv.pem
# RSA public key in PEM format  - rsakey.pub.pem
# data file to be signed or encrypted - input.data

Encrypt by OpenSSL, decrypt by Crypt::PK::RSA

Create encrypted file (from commandline):

openssl rsautl -encrypt -inkey rsakey.pub.pem -pubin -out input.encrypted.rsa -in input.data

Decrypt file (Perl code):

use Crypt::PK::RSA;
use File::Slurp 'read_file';

my $pkrsa = Crypt::PK::RSA->new("rsakey.priv.pem");
my $encfile = read_file("input.encrypted.rsa", binmode=>':raw');
my $plaintext = $pkrsa->decrypt($encfile, 'v1.5');
print $plaintext;

Encrypt by Crypt::PK::RSA, decrypt by OpenSSL

Create encrypted file (Perl code):

use Crypt::PK::RSA;
use File::Slurp 'write_file';

my $plaintext = 'secret message';
my $pkrsa = Crypt::PK::RSA->new("rsakey.pub.pem");
my $encrypted = $pkrsa->encrypt($plaintext, 'v1.5');
write_file("input.encrypted.rsa", {binmode=>':raw'}, $encrypted);

Decrypt file (from commandline):

openssl rsautl -decrypt -inkey rsakey.priv.pem -in input.encrypted.rsa

Sign by OpenSSL, verify by Crypt::PK::RSA

Create signature (from commandline):

openssl dgst -sha1 -sign rsakey.priv.pem -out input.sha1-rsa.sig input.data

Verify signature (Perl code):

use Crypt::PK::RSA;
use Crypt::Digest 'digest_file';
use File::Slurp 'read_file';

my $pkrsa = Crypt::PK::RSA->new("rsakey.pub.pem");
my $signature = read_file("input.sha1-rsa.sig", binmode=>':raw');
my $valid = $pkrsa->verify_hash($signature, digest_file("SHA1", "input.data"), "SHA1", "v1.5");
print $valid ? "SUCCESS" : "FAILURE";

Sign by Crypt::PK::RSA, verify by OpenSSL

Create signature (Perl code):

use Crypt::PK::RSA;
use Crypt::Digest 'digest_file';
use File::Slurp 'write_file';

my $pkrsa = Crypt::PK::RSA->new("rsakey.priv.pem");
my $signature = $pkrsa->sign_hash(digest_file("SHA1", "input.data"), "SHA1", "v1.5");
write_file("input.sha1-rsa.sig", {binmode=>':raw'}, $signature);

Verify signature (from commandline):

openssl dgst -sha1 -verify rsakey.pub.pem -signature input.sha1-rsa.sig input.data

Keys generated by Crypt::PK::RSA

Generate keys (Perl code):

use Crypt::PK::RSA;
use File::Slurp 'write_file';

my $pkrsa = Crypt::PK::RSA->new;
$pkrsa->generate_key(256, 65537);
write_file("rsakey.pub.der",  {binmode=>':raw'}, $pkrsa->export_key_der('public'));
write_file("rsakey.priv.der", {binmode=>':raw'}, $pkrsa->export_key_der('private'));
write_file("rsakey.pub.pem",  $pkrsa->export_key_pem('public_x509'));
write_file("rsakey.priv.pem", $pkrsa->export_key_pem('private'));
write_file("rsakey-passwd.priv.pem", $pkrsa->export_key_pem('private', 'secret'));

Use keys by OpenSSL:

openssl rsa -in rsakey.priv.der -text -inform der
openssl rsa -in rsakey.priv.pem -text
openssl rsa -in rsakey-passwd.priv.pem -text -inform pem -passin pass:secret
openssl rsa -in rsakey.pub.der -pubin -text -inform der
openssl rsa -in rsakey.pub.pem -pubin -text

Keys generated by OpenSSL

Generate keys:

openssl genrsa -out rsakey.priv.pem 1024
openssl rsa -in rsakey.priv.pem -out rsakey.priv.der -outform der
openssl rsa -in rsakey.priv.pem -out rsakey.pub.pem -pubout
openssl rsa -in rsakey.priv.pem -out rsakey.pub.der -outform der -pubout
openssl rsa -in rsakey.priv.pem -passout pass:secret -des3 -out rsakey-passwd.priv.pem

Load keys (Perl code):

use Crypt::PK::RSA;
use File::Slurp 'write_file';

my $pkrsa = Crypt::PK::RSA->new;
$pkrsa->import_key("rsakey.pub.der");
$pkrsa->import_key("rsakey.priv.der");
$pkrsa->import_key("rsakey.pub.pem");
$pkrsa->import_key("rsakey.priv.pem");
$pkrsa->import_key("rsakey-passwd.priv.pem", "secret");

SEE ALSO