Functions to decrypt and encrypt Wordpress passwords from plugin.

wordpress_encryption_fragment.php

<?php

 /* These need to go in your custom plugin (or existing plugin) */
  private function encrypt($input_string, $key){
    $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
    $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
    $h_key = hash('sha256', $key, TRUE);
    return base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $h_key, $input_string, MCRYPT_MODE_ECB, $iv));
  }

  private function decrypt($encrypted_input_string, $key){
    $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
    $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
    $h_key = hash('sha256', $key, TRUE);
    return trim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $h_key, base64_decode($encrypted_input_string), MCRYPT_MODE_ECB, $iv));
  }