/ 
CryptX-0.005
River stage three • 89 direct dependents • 391 total dependents
/ Crypt::Mode::CTR
Security Advisories (3)
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-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.

NAME

Crypt::Mode::CTR - Block cipher mode CTR [Counter mode]

SYNOPSIS

Crypt::Mode::CTR;
my $m = Crypt::Mode::CTR->new('AES');

#(en|de)crypt at once
my $ciphertext = $m->encrypt($plaintext, $key, $iv);
my $plaintext = $m->decrypt($ciphertext, $key, $iv);

#encrypt more chunks
$m->start_encrypt($key, $iv);
my $ciphertext = $m->add('some data');
$ciphertext .= $m->add('more data');

#decrypt more chunks
$m->start_decrypt($key, $iv);
my $plaintext = $m->add($some_ciphertext);
$plaintext .= $m->add($more_ciphertext);

DESCRIPTION

This module implements CTR cipher mode. NOTE: it works only with ciphers from CryptX (Crypt::Cipher::NNNN).

METHODS

new

my $m = Crypt::Mode::CTR->new($cipher_name);
#or
my $m = Crypt::Mode::CTR->new($cipher_name, $ctr_mode, $ctr_width);
#or
my $m = Crypt::Mode::CTR->new($cipher_name, $ctr_mode, $ctr_width, $cipher_rounds);

# $ctr_mode .... 0 little-endian counter (DEFAULT)
#                1 big-endian counter
#                2 little-endian + RFC3686 incrementing
#                3 big-endian + RFC3686 incrementing
# $ctr_width ... counter width in bytes (DEFAULT = full block width)
# $cipher_rounds ... optional num of rounds for given cipher

encrypt

my $ciphertext = $m->encrypt($plaintext, $key, $iv);

decrypt

my $plaintext = $m->encrypt($ciphertext, $key, $iv);

start_encrypt

start_decrypt

add

finish

#encrypt more chunks
$m->start_encrypt($key, $iv);
my $ciphertext = '';
$ciphertext .= $m->add('some data');
$ciphertext .= $m->add('more data');

#decrypt more chunks
$m->start_decrypt($key, $iv);
my $plaintext = '';
$plaintext .= $m->add($some_ciphertext);
$plaintext .= $m->add($more_ciphertext);

SEE ALSO

CryptX