After browsing the internet, i came to the conclusion that -SC2 has no bulletproof way of coding banks so that they are hack proof-
After messing around for an hour, i created a solution that would take months to decode if determined!
Most maps save banks for multiplayer use and have important values that are hard earned and shouldn't be cheat able. With a bit of time, you can achieve this.
This method saves two bank files as followed:

Bank File A:
This file stores all of the players values in plain sight
Kills, deaths, xp, time played etc

Bank File B:
This file stores all of bank A's values but "coded"

THE METHOD:
When saving values to the banks, Save the values normally to Bank A
but when saving to Bank B, throw in a simple equation to change the value such as 3(X+45)
where the value has 45 added to it and multiplied by 3.
If you had 1 kill then the "coded value" would be 138
Now save 138 as a random key to Bank B.
Now when the map starts up, have it reverse the "coded value" and compare it to Bank A's value.
If they are different, then place the words "HACKED" on the screen and delete their Banks!
This way the hacker will have no idea how the map detected him and which value is "coded." would you?
Even if the hacker deleted Bank B, the values would be way off!
The reverse equation to this would be (X/3)-45

Now say the hacker catches on somehow and figures out the equation...
You can create a trigger that generates a new equation every time it saves by following:
A(X+B)+C
where the letters ABC can be random given integers. Set ABC = random integers 1-1000 and save ABC to Bank B discretely.
Make sure each value has its own unique equation to throw the hacker off.

And never forget to name your banks something unique so they don't get edited by another map
Hope this inspires somebody!

The basic protection is the signature. It stops basic editing of values as different file content will result in a different hash value. I would use it as it is there.
Sadly there exists an easy way around that which I won't tell here.

Your approach of 2 banks is interesting as you need to modify 2 values for 1 information and each bank can have its own signature which raises the amount of work that needs to be done to cheat.

But it would be still possible to open your locked map to obtain the saving code. So there is no bulletproof way.

You could add 2 alphabets that change the values into a string with some chars. Starcode uses that to compress the amount saved, but it can be used to make stuff harder to decipher, too. In your version it's easy to tell which value has which meaning as the first bank didn't save encrypted values.

But in the end only online banks could prevent cheating.

I still need to write my own bank protection stuff, but storing stuff in multiple banks with different encryption methods seems good to me.

edit:
more stuff to consider:
- save player handle to check if a player gave the file to another person
- add a bank version information to be able to update your banks

Post has been edited 1 time(s), last time on Jan 5 2012, 3:03 am by Ahli.

Not if you are generating new equations. Unless they edited your map in all and removed the equations...

Well you could encrypt both. Or you could just write two values in the same bank and have them in different sections and have them compared.

I am glad we are trying to eliminate the cheaters. Stay strong brothers!

Post has been edited 2 time(s), last time on Jan 5 2012, 9:45 pm by Bolshevik09.

I mean, if they get the loading code, they can figure out how to put the correct values into their banks.

A related thought -- if a player is caught cheating in a game with other players, distribute that player's name to all player banks and make those players cross-auto-spread-update the cheater-list between games.
So even if the cheater hacks right later on, the name will be out. Then people who have not come in contact with that player (but with others who did) could be shown a message saying that person is a known cheater, maybe offer the option to boot.
This is a bit excessive though. Not very practical since the list may grow too big, especially when IT gets hacked.
Nearly useless if the hacker tests the hack solo, or has multiple accounts if the game does not support solo play.

I guess until banks can be saved on servers the best thing to do is make sure the role of the saved data can't overwhelm the game-play.