portal/patient/fwk/libs/verysimple/Encryption/McryptUtil.php

   1 <?php
   2
   3 /** @package    verysimple::Encryption */
   4
   5 /**
   6  * require supporting files
   7  */
   8
   9 /**
  10  * A static utility class for encryption/decrytion using the php mcrypt functionality
  11  *
  12  * @package verysimple::Encryption::McryptUtil
  13  */
  14 class McryptUtil
  15 {
  16     static $IV;
  17     static $CIPHER = MCRYPT_RIJNDAEL_256;
  18     static $MODE = MCRYPT_MODE_ECB;
  19
  20     /**
  21      * Creates the initialization vector.
  22      * This method is called automatically
  23      * when encrypt/decrypt are called and does not need to be explicitly called
  24      */
  25     static function Init()
  26     {
  27         if (! McryptUtil::$IV) {
  28             if (! function_exists("mcrypt_get_iv_size")) {
  29                 throw new Exception("The mcrypt extension does not appear to be enabled.");
  30             }
  31
  32             $iv_size = mcrypt_get_iv_size(McryptUtil::$CIPHER, McryptUtil::$MODE);
  33             McryptUtil::$IV = mcrypt_create_iv($iv_size, MCRYPT_RAND);
  34         }
  35     }
  36
  37     /**
  38      * Encrypts data
  39      *
  40      * @param
  41      *          string data to be encrypted
  42      * @param
  43      *          string encryption key/passphrase
  44      * @param
  45      *          bool [optional] true to base64 encode the result
  46      * @return string encrypted data
  47      */
  48     static function Encrypt($data, $key, $encode = true)
  49     {
  50         McryptUtil::Init();
  51
  52         $encrypted = mcrypt_encrypt(McryptUtil::$CIPHER, $key, $data, McryptUtil::$MODE, McryptUtil::$IV);
  53
  54         return ($encode) ? base64_encode($encrypted) : $encrypted;
  55     }
  56
  57     /**
  58      * Decrypts data that was previously encrypted
  59      *
  60      * @param
  61      *          string data to be decrypted
  62      * @param
  63      *          string encryption key/passphrase
  64      * @param
  65      *          bool [optional] true if the encrypted string is base64 encoded
  66      * @param
  67      *          bool [optional] true to strip the null character padding at the end
  68      * @return string decrypted data
  69      */
  70     static function Decrypt($data, $key, $decode = true, $strip_nulls = true)
  71     {
  72         McryptUtil::Init();
  73
  74         if ($decode) {
  75             $data = base64_decode($data);
  76         }
  77
  78         $decrypted = mcrypt_decrypt(McryptUtil::$CIPHER, $key, $data, McryptUtil::$MODE, McryptUtil::$IV);
  79
  80         // mcrypt pads the end of the block with null chars, so we need to strip them
  81         return $strip_nulls ? rtrim($decrypted, "\0") : $decrypted;
  82     }
  83 }