Question

I need to send an ajax POST request to my server.

I’ll need to make sure that the request originated from the script itself, and not from a user writing the request him/her self.
Is there any secure way to do this? Can the script sign or encode the POST request, later to be decrypted by the server’s private key? and can I somehow prevent the user from encrypting using my public key?

I’m not doing this just for filtering purposes – so plain old server-side validation just won’t do.

Answer 1

The other answers are correct: this is fundamentally impossible. Probably the best you can do from a pragmatic point of view is to look into really nasty ways to obfuscate your JavaScript to discourage people who might try to look at it, but you can be assured that someone motivated can work around this without too much effort. http://en.wikipedia.org/wiki/Obfuscated_code