प्रोवेबली फेयर
A system that lets players check cryptographically that a game result was fixed before the bet and not altered afterwards.
Provably fair is a method used by crypto casinos to show that a game's outcome was determined in advance and could not be changed in response to your bet. It combines a secret server seed, a player-chosen client seed and a counter called a nonce.
How it works, in short
- Before you play, the casino commits to a secret server seed by showing you its SHA-256 hash.
- You set a client seed, which the casino cannot predict.
- Each bet uses HMAC-SHA256 of the server seed and a message built from your client seed and the nonce. The output is turned into the game result.
- When you rotate seeds, the casino reveals the server seed. You hash it to confirm it matches the commitment, then recompute every result.
What it does and does not prove
It proves the results of verifiable games match the committed seeds. It does not reduce the house edge, does not cover third-party slots or live dealer games, and does not guarantee the casino will pay out. Implementations differ between casinos, so verification must follow each casino's documented scheme.