将字符串作为超链接通过url传递时加密，并解密以在下一页上回显

我使用以下加密和解密脚本，以便当用户单击包含我的字符串的链接时，该字符串在url中加密并在下一页解密。

我的字符串正在被加密，但由于某种原因，它不会在下一页解密。谁能告诉我哪里错了吗?谢谢你,

encryption.php:

<?php class encryption{
    private $config;
    public function __construct( $options=array() ){
        $this->config=array_merge(
            array(
                'cipher'    =>  MCRYPT_RIJNDAEL_256,
                'mode'      =>  MCRYPT_MODE_ECB,
                'key'       =>  FALSE,
                'iv'        =>  FALSE,
                'size'      =>  FALSE,
                'base64'    =>  TRUE,
                'salt'      =>  FALSE
            ),
            $options
        );
    }
    private function getivs( $config=object ){
        $config->size=mcrypt_get_iv_size( $config->cipher, $config->mode );
        $config->iv=mcrypt_create_iv( $config->size, MCRYPT_RAND );
    }
    public function encrypt( $data=NULL ){
        $config=(object)$this->config;
        $this->getivs( $config );
        $data=trim( $data );
        $module = mcrypt_module_open( $config->cipher, '', $config->mode, '' );
        mcrypt_generic_init( $module, $config->key, $config->iv );
        $output = $config->base64 ? base64_encode( mcrypt_generic( $module, $data ) ) : mcrypt_generic( $module, $data );
        mcrypt_generic_deinit( $module );
        mcrypt_module_close( $module );
        return $output;
    }
    public function decrypt( $data=NULL ){
        $config=(object)$this->config;
        $this->getivs( $config );
        mb_detect_order( 'auto' );
        $encoding=mb_detect_encoding( $data );
        if( !$data or is_null( $data ) or empty( $data ) or !$encoding or $data=='' or base64_decode( $data )=='' ) return FALSE;
        $module = mcrypt_module_open( $config->cipher, '', $config->mode, '' );
        mcrypt_generic_init( $module, $config->key, $config->iv );
        $output = $config->base64 ? rtrim( mdecrypt_generic( $module, base64_decode( $data ) ),"'0" ) : rtrim( mdecrypt_generic( $module, $data ),"'0" );
        mcrypt_generic_deinit( $module );
        mcrypt_module_close( $module );
        return urldecode( $output );
    }
}//end class
?>

new_supplier_listings.php:

session_start(); 
require_once 'dependables/encryption.php';
$string = 'NS12345';
        $enc=new encryption( array( 'key'=>'PlowFish' ) );
        $encrypted_string = $enc->encrypt( $string );

echo '<a href="ns_application.php?ns_request='.$encrypted_string.'">Click Here</a>';

ns_application.php:

require_once 'dependables/encryption.php'; 

$reference = isset($_GET['ns_request']) ? $_GET['ns_request'] : null;
$enc=new encryption( array( 'key'=>'PlowFish' ) );
$encrypted_string = $enc->encrypt( $reference );
echo $encrypted_string;
$decrypted_string=$enc->decrypt( $encrypted_string );
echo $decrypted_string;