Flash games hack, score is 49700?? How to improve flash games security?

Question

I have 2 flash games (written in as3). Both the highscore value being hacked. The normal range of each game score is not more than 5000 (normal users, will only get 2000 - 3000

Answer 1

If I wanted to hack your game I could decompile your game and find out the md5 "secret". Note that I put secret in quote marks, as the fact that it is provided in your flash game binary means that it is not actually a secret.

Its probably not possible to make your scores unhackable, all you can hope to do is make it harder.