http://treehousetim.com/2011/12/13/hiding-values-in-urls-using-php/

example.php

<?
//http://treehousetim.com/2011/12/13/hiding-values-in-urls-using-php/

header( 'content-type: text/plain' );
$h = '';
if ( array_key_exists( 'h', $_GET ) && ! empty( $_GET['h'] ) )
{
    $test = unserialize( gzuncompress( base64_decode( urldecode( urldecode( $_GET['h'] ) ) ) ) );
    if ( is_array( $test ) )
    {
        $h = $_GET['h'];
        $_GET = $test;
    }
}
elseif( count( $_GET) )
{
    $h = urlencode( urlencode( base64_encode( gzcompress( serialize( $_GET ), 9 ) ) ) );
}
 
list( $url ) = explode( '?', $_SERVER['REQUEST_URI'] );
 
if ( ! empty( $h ) )
{
    $url .= '?h=' . $h;
}
 
echo $url . "\n\n";
 
var_dump( $_GET );