Encryption library Class

Encryption.php

<?php
class Encryption{
    var $defskey 	= "NibidAlo"; // Encryption Key

    public  function safe_b64encode($string) {
        $data = base64_encode($string);
        $data = str_replace(array('+','/','='),array('-','_',''),$data);
        return urlencode($data);
    }

    public function safe_b64decode($string) {
        $data = urldecode($string);
        $data = str_replace(array('-','_'),array('+','/'),$string);
        $mod4 = strlen($data) % 4;
        if ($mod4) {
            $data .= substr('====', $mod4);
        }
        return base64_decode($data);
    }

    public  function encode($value, $skey=""){
        if(!$value){return false;}
        if( function_exists( 'mcrypt_module_open' ) ){
            if(strlen($skey)==0) $skey=$this->defskey;
            //echo 'ok- mcrypt enabled';
            $text = $value;
            $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
            $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
            $crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $skey, $text, MCRYPT_MODE_ECB, $iv);
            return $this->safe_b64encode($crypttext);
        }else{
            return $this->safe_b64encode($value);
        }
    }

    public function decode($value, $skey=""){
        if(!$value){return false;}
        if(strlen($skey)==0) $skey=$this->defskey;
        if( function_exists( 'mcrypt_module_open' ) ){
            //echo 'ok- mcrypt enabled';
            $crypttext = $this->safe_b64decode($value);
            $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
            $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
            $decrypttext = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $skey, $crypttext, MCRYPT_MODE_ECB, $iv);
            return trim($decrypttext);
        }else{
            return $this->safe_b64decode($value);
        }
    }
}