Secure Method to transfer data via AJAX in construct

Hi,

I need to design a leader board for my web game. I was done it with AJAX and PHP and it work well. but with inspect element in Chrome i can easily hack the POST command of savescore. As i found sha1 HASH encryption and description is a one of best solution to securely transfer ajax data. So How do i use sha1 HASH with construct 2 ? Is it possible ? or is there any other solution ?

Thanks,