/core/lib/Drupal/Component/Utility/Crypt.php
PHP | 130 lines | 41 code | 9 blank | 80 comment | 6 complexity | 9f2d4aa74dcf031fbed13fcf4a2129e6 MD5 | raw file
Possible License(s): LGPL-2.1
- <?php
- /**
- * @file
- * Contains \Drupal\Component\Utility\Crypt.
- */
- namespace Drupal\Component\Utility;
- /**
- * Utility class for cryptographically-secure string handling routines.
- */
- class Crypt {
- /**
- * Returns a string of highly randomized bytes (over the full 8-bit range).
- *
- * This function is better than simply calling mt_rand() or any other built-in
- * PHP function because it can return a long string of bytes (compared to < 4
- * bytes normally from mt_rand()) and uses the best available pseudo-random
- * source.
- *
- * @param int $count
- * The number of characters (bytes) to return in the string.
- *
- * @return string
- * A randomly generated string.
- */
- public static function randomBytes($count) {
- static $random_state, $bytes;
- // Initialize on the first call. The contents of $_SERVER includes a mix of
- // user-specific and system information that varies a little with each page.
- // Further initialize with the somewhat random PHP process ID.
- if (!isset($random_state)) {
- $random_state = print_r($_SERVER, TRUE) . getmypid();
- $bytes = '';
- }
- if (strlen($bytes) < $count) {
- // /dev/urandom is available on many *nix systems and is considered the
- // best commonly available pseudo-random source.
- if ($fh = @fopen('/dev/urandom', 'rb')) {
- // PHP only performs buffered reads, so in reality it will always read
- // at least 4096 bytes. Thus, it costs nothing extra to read and store
- // that much so as to speed any additional invocations.
- $bytes .= fread($fh, max(4096, $count));
- fclose($fh);
- }
- // openssl_random_pseudo_bytes() will find entropy in a system-dependent
- // way.
- elseif (function_exists('openssl_random_pseudo_bytes')) {
- $bytes .= openssl_random_pseudo_bytes($count - strlen($bytes));
- }
- // If /dev/urandom is not available or returns no bytes, this loop will
- // generate a good set of pseudo-random bytes on any system.
- // Note that it may be important that our $random_state is passed
- // through hash() prior to being rolled into $output, that the two hash()
- // invocations are different, and that the extra input into the first one -
- // the microtime() - is prepended rather than appended. This is to avoid
- // directly leaking $random_state via the $output stream, which could
- // allow for trivial prediction of further "random" numbers.
- while (strlen($bytes) < $count) {
- $random_state = hash('sha256', microtime() . mt_rand() . $random_state);
- $bytes .= hash('sha256', mt_rand() . $random_state, TRUE);
- }
- }
- $output = substr($bytes, 0, $count);
- $bytes = substr($bytes, $count);
- return $output;
- }
- /**
- * Calculates a base-64 encoded, URL-safe sha-256 hmac.
- *
- * @param mixed $data
- * Scalar value to be validated with the hmac.
- * @param mixed $key
- * A secret key, this can be any scalar value.
- *
- * @return string
- * A base-64 encoded sha-256 hmac, with + replaced with -, / with _ and
- * any = padding characters removed.
- */
- public static function hmacBase64($data, $key) {
- // $data and $key being strings here is necessary to avoid empty string
- // results of the hash function if they are not scalar values. As this
- // function is used in security-critical contexts like token validation it
- // is important that it never returns an empty string.
- if (!is_scalar($data) || !is_scalar($key)) {
- throw new \InvalidArgumentException('Both parameters passed to \Drupal\Component\Utility\Crypt::hmacBase64 must be scalar values.');
- }
- $hmac = base64_encode(hash_hmac('sha256', $data, $key, TRUE));
- // Modify the hmac so it's safe to use in URLs.
- return strtr($hmac, array('+' => '-', '/' => '_', '=' => ''));
- }
- /**
- * Calculates a base-64 encoded, URL-safe sha-256 hash.
- *
- * @param string $data
- * String to be hashed.
- *
- * @return string
- * A base-64 encoded sha-256 hash, with + replaced with -, / with _ and
- * any = padding characters removed.
- */
- public static function hashBase64($data) {
- $hash = base64_encode(hash('sha256', $data, TRUE));
- // Modify the hash so it's safe to use in URLs.
- return strtr($hash, array('+' => '-', '/' => '_', '=' => ''));
- }
- /**
- * Generates a random, base-64 encoded, URL-safe, sha-256 hashed string.
- *
- * @param int $count
- * The number of characters (bytes) of the string to be hashed.
- *
- * @return string
- * A base-64 encoded sha-256 hash, with + replaced with -, / with _ and
- * any = padding characters removed.
- *
- * @see \Drupal\Component\Utility\Crypt::randomBytes()
- * @see \Drupal\Component\Utility\Crypt::hashBase64()
- */
- public static function randomStringHashed($count) {
- return static::hashBase64(static::randomBytes($count));
- }
- }