Contao\Encryption::encrypt PHP Method

    public static function encrypt($varValue, $strKey = null)
    {
        // Recursively encrypt arrays
        if (is_array($varValue)) {
            foreach ($varValue as $k => $v) {
                $varValue[$k] = static::encrypt($v);
            }
            return $varValue;
        } elseif ($varValue == '') {
            return '';
        }
        // Initialize the module
        if (static::$resTd === null) {
            static::initialize();
        }
        if (!$strKey) {
            $strKey = \System::getContainer()->getParameter('contao.encryption_key');
        }
        $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size(static::$resTd));
        mcrypt_generic_init(static::$resTd, md5($strKey), $iv);
        $strEncrypted = mcrypt_generic(static::$resTd, $varValue);
        $strEncrypted = base64_encode($iv . $strEncrypted);
        mcrypt_generic_deinit(static::$resTd);
        return $strEncrypted;
    }

 /**
  * Duplicate all child records of a duplicated record
  *
  * @param string  $table
  * @param integer $insertID
  * @param integer $id
  * @param integer $parentId
  */
 protected function copyChilds($table, $insertID, $id, $parentId)
 {
     $time = time();
     $copy = array();
     $cctable = array();
     $ctable = $GLOBALS['TL_DCA'][$table]['config']['ctable'];
     if (!$GLOBALS['TL_DCA'][$table]['config']['ptable'] && strlen(\Input::get('childs')) && $this->Database->fieldExists('pid', $table) && $this->Database->fieldExists('sorting', $table)) {
         $ctable[] = $table;
     }
     if (!is_array($ctable)) {
         return;
     }
     // Walk through each child table
     foreach ($ctable as $v) {
         $this->loadDataContainer($v);
         $cctable[$v] = $GLOBALS['TL_DCA'][$v]['config']['ctable'];
         if (!$GLOBALS['TL_DCA'][$v]['config']['doNotCopyRecords'] && strlen($v)) {
             // Consider the dynamic parent table (see #4867)
             if ($GLOBALS['TL_DCA'][$v]['config']['dynamicPtable']) {
                 $ptable = $GLOBALS['TL_DCA'][$v]['config']['ptable'];
                 $cond = $ptable == 'tl_article' ? "(ptable=? OR ptable='')" : "ptable=?";
                 $objCTable = $this->Database->prepare("SELECT * FROM {$v} WHERE pid=? AND {$cond}" . ($this->Database->fieldExists('sorting', $v) ? " ORDER BY sorting" : ""))->execute($id, $ptable);
             } else {
                 $objCTable = $this->Database->prepare("SELECT * FROM {$v} WHERE pid=?" . ($this->Database->fieldExists('sorting', $v) ? " ORDER BY sorting" : ""))->execute($id);
             }
             while ($objCTable->next()) {
                 // Exclude the duplicated record itself
                 if ($v == $table && $objCTable->id == $parentId) {
                     continue;
                 }
                 foreach ($objCTable->row() as $kk => $vv) {
                     if ($kk == 'id') {
                         continue;
                     }
                     // Never copy passwords
                     if ($GLOBALS['TL_DCA'][$v]['fields'][$kk]['inputType'] == 'password') {
                         $vv = \Widget::getEmptyValueByFieldType($GLOBALS['TL_DCA'][$v]['fields'][$kk]['sql']);
                     } elseif ($GLOBALS['TL_DCA'][$v]['fields'][$kk]['eval']['unique']) {
                         $vv = \Input::get('act') == 'copyAll' ? $vv . '-' . substr(md5(uniqid(mt_rand(), true)), 0, 8) : \Widget::getEmptyValueByFieldType($GLOBALS['TL_DCA'][$v]['fields'][$kk]['sql']);
                     } elseif ($GLOBALS['TL_DCA'][$v]['fields'][$kk]['eval']['doNotCopy'] || $GLOBALS['TL_DCA'][$v]['fields'][$kk]['eval']['fallback']) {
                         $vv = '';
                         // Use array_key_exists to allow NULL (see #5252)
                         if (array_key_exists('default', $GLOBALS['TL_DCA'][$v]['fields'][$kk])) {
                             $vv = is_array($GLOBALS['TL_DCA'][$v]['fields'][$kk]['default']) ? serialize($GLOBALS['TL_DCA'][$v]['fields'][$kk]['default']) : $GLOBALS['TL_DCA'][$v]['fields'][$kk]['default'];
                         }
                         // Encrypt the default value (see #3740)
                         if ($GLOBALS['TL_DCA'][$v]['fields'][$kk]['eval']['encrypt']) {
                             $vv = \Encryption::encrypt($vv);
                         }
                     }
                     $copy[$v][$objCTable->id][$kk] = $vv;
                 }
                 $copy[$v][$objCTable->id]['pid'] = $insertID;
                 $copy[$v][$objCTable->id]['tstamp'] = $time;
             }
         }
     }
     // Duplicate the child records
     foreach ($copy as $k => $v) {
         if (!empty($v)) {
             foreach ($v as $kk => $vv) {
                 $objInsertStmt = $this->Database->prepare("INSERT INTO " . $k . " %s")->set($vv)->execute();
                 if ($objInsertStmt->affectedRows) {
                     $insertID = $objInsertStmt->insertId;
                     if ((!empty($cctable[$k]) || $GLOBALS['TL_DCA'][$k]['list']['sorting']['mode'] == 5) && $kk != $parentId) {
                         $this->copyChilds($k, $insertID, $kk, $parentId);
                     }
                 }
             }
         }
     }
 }