How to hack proof a data submission program

I am writing a score submission system for games where I need to ensure that reports back to the server are not falsified (aka, hacked).

I know that I can store a password or private passkey in the program to authenticate or encrypt the request but if the program is decompiled, a crafty hacker can extract the password/passkey and use it to falsify reports.

Does a perfect solu开发者_开发问答tion exist?

Thanks in advance.

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No. All you can do is make it difficult for cheaters.

You don't say what environment you're running on, but it sounds like you're trying to solve a code authentication problem*: knowing that the code that is executing is actually what you think it is. This is a problem that has plagued online games forever and does not have a good solution.

Common ways in which such systems are commonly broken:

• Capture, modification and replay of submissions to the server
• Modifying the binary to allow cheating
• Using a debugger to modify the submission in-memory before the program applies signatures/encryption/whatever

Punkbuster is an example of a system which attempts to solve some of these problems: http://en.wikipedia.org/wiki/PunkBuster

Also consider http://en.wikipedia.org/wiki/Cheating_in_online_games

Chances are, this is probably too hard for your game. Hiding a public key in your binary and signing everything that leaves it will probably put you well ahead of the pack, security-wise.

* Apologies, I don't actually remember what the formal name for this is. I keep thinking "running code authentication", but Google comes up with nothing for the term.

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There is one thing you can do - record all of the user inputs and send those to the server as part of the submission. The server can then replay the inputs through a local copy of the game engine to determine the score. Obviously this isn't appropriate for every type of game, though. Depending on the game, you may need to include replay protection.

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Another method that may be appropriate for some types of games is to include a video recording of the high-scoring play within the submission. Provide links to the videos from the high score table, along with a link to report suspicious entries. This will let you "crowd-source" cheat detection - if a cheater's score hits the table at number 1, then the players behind scores 2 through 10 have a pretty big incentive to validate the video for you. If a score is reported enough times, you can check the video yourself and decide if it should be removed (and the user banned).