authenticated_aes.inc in Real AES 7.2

Plugin definition for an authenticated AES-128 encryption method.

File

plugins/encryption_methods/authenticated_aes.inc

<?php

/**
 * @file
 * Plugin definition for an authenticated AES-128 encryption method.
 */
use Defuse\Crypto\Crypto;
use Defuse\Crypto\Key;
use Defuse\Crypto\Encoding;
use Defuse\Crypto\Exception as Ex;
$plugin = real_aes_authenticated_aes_encrypt_encryption_methods();

/**
 * Implements hook_encrypt_encryption_methods().
 */
function real_aes_authenticated_aes_encrypt_encryption_methods() {
  return array(
    'title' => t('Authenticated AES (Real AES)'),
    'description' => t('<a href="@authenticated-url">Authenticated encryption</a> based on <a href="@aes-url">AES-128</a> in <a href="@cbc-url">CBC mode</a>. Verifies ciphertext integrity via an Encrypt-then-MAC scheme using <a href="@hmac-url">HMAC-SHA256</a>. See the Real AES README.txt for details.', array(
      '@authenticated-url' => 'https://en.wikipedia.org/wiki/Authenticated_encryption',
      '@aes-url' => 'https://en.wikipedia.org/wiki/Advanced_Encryption_Standard',
      '@cbc-url' => 'https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_Block_Chaining_.28CBC.29',
      '@hmac-url' => 'https://en.wikipedia.org/wiki/Hash-based_message_authentication_code',
    )),
    'encrypt callback' => '_real_aes_encryption_methods_authenticated_aes',
    'dependency callback' => '_real_aes_authenticated_aes_check_requirements',
  );
}

/**
 * Callback for Encrypt implementation: Authenticated AES.
 *
 * This method uses the Real_AES loaded Defuse encryption library.
 * Base64 encoding is used by default, unless disabled by setting
 * 'base64' to FALSE in $options.
 */
function _real_aes_encryption_methods_authenticated_aes($op, $text, $key, $options = array()) {
  $disable_base64 = array_key_exists('base64', $options) && $options['base64'] == FALSE;

  // If the random_bytes function does not exist, as in the case of
  // PHP versions lower than 7.0, load the random_compat library.
  if (!function_exists('random_bytes')) {
    real_aes_load_library('random_compat');
  }

  // Check op.
  if ($op == 'decrypt') {
    if (real_aes_load_library() && function_exists('random_bytes')) {

      // Check if we are disabling base64 encoding.
      if (!$disable_base64) {
        $text = base64_decode($text);
      }
      try {

        // Defuse PHP-Encryption requires a key object instead of a string.
        $key = Encoding::saveBytesToChecksummedAsciiSafeString(Key::KEY_CURRENT_VERSION, $key);
        $key = Key::loadFromAsciiSafeString($key);
        return Crypto::decrypt($text, $key, TRUE);
      } catch (Ex\CryptoException $ex) {
        return FALSE;
      }
    }
  }
  else {
    if (real_aes_load_library() && function_exists('random_bytes')) {

      // Encrypt.
      try {

        // Defuse PHP-Encryption requires a key object instead of a string.
        $key = Encoding::saveBytesToChecksummedAsciiSafeString(Key::KEY_CURRENT_VERSION, $key);
        $key = Key::loadFromAsciiSafeString($key);
        $processed_text = Crypto::encrypt($text, $key, TRUE);

        // Check if we are disabling base64 encoding.
        if (!$disable_base64) {
          $processed_text = base64_encode($processed_text);
        }
        return $processed_text;
      } catch (Ex\CryptoException $ex) {
        return FALSE;
      }
    }
  }
  return FALSE;
}

/**
 * Callback to check if Real AES is enabled, and the library has been installed.
 */
function _real_aes_authenticated_aes_check_requirements() {
  $errors = array();
  if (!function_exists('real_aes_load_library')) {
    $errors[] = t('Real AES module is not installed.');
  }
  elseif (!real_aes_load_library('php-encryption')) {
    $errors[] = t('PHP-encryption library not installed.');
  }
  elseif (!function_exists('random_bytes') && !real_aes_load_library('random_compat')) {
    $errors[] = t('PHP versions lower than 7.0 require the random_compat library.');
  }
  return $errors;
}

Functions

Name	Description
real_aes_authenticated_aes_encrypt_encryption_methods	Implements hook_encrypt_encryption_methods().
_real_aes_authenticated_aes_check_requirements	Callback to check if Real AES is enabled, and the library has been installed.
_real_aes_encryption_methods_authenticated_aes	Callback for Encrypt implementation: Authenticated AES.