How it works

We have generated a chain of 10 million SHA256 hashes for each game, starting with a server secret that has been repeatedly fed the output of SHA256 back into itself 10 million times.

The SHA256 of the final hash for crash starting at game 2,146,223 is: 33d8be75c9f6cb219a1763e77e307ac0a1107c85bd9fee53e81be0ec592ff4c5

The SHA256 of the final hash for roulette is: 5bf9a3fae704667be2d3704ea8b6e703796defaa5f328e1a8d46b3a0fa12269f

By publicising it here we are preventing any ability to pick an alternate SHA256 chain. Now the game server is playing through this chain of hashes in reverse order, using these values to calculate the game's crashpoint provably fair.

How to verify

Anyone can easily verify integrity of the chain. We're publishing a game's hash immediately after the game ends. By checking that the SHA256 hash of that game's hash is the game's hash of the previous game you can make sure that we were not able to modify the result.
The sample code to generate games hashes and calculate Crash results can be found here.
The sample code to generate games hashes and calculate Roulette results can be found here.
The sample code to generate games hashes and calculate Hilo results can be found here.
To verify your Tradeup games please head over to your Tradeup history.

Fairness

Bottom line is that results for all future games are already predefined and normally distributed due to math that backs up the strong cryptographic SHA256 function. We cannot manipulate this chain of results without the public noticing it.