Casino glossary · Result verification
Provably fair: two checks for one recorded round
Provably fair is a method for checking how a supported game generated a result from recorded inputs. In a common seed-based system, you check that the revealed secret matches a commitment shown before play, then reproduce the round's outcome. The check concerns that result calculation.
The inputs in a Stake-style system
| Input | What it does | What you need for verification |
|---|---|---|
| Server seed | Supplies the operator's secret input | The revealed seed used for the recorded round |
| Server-seed hash | Commits to that seed before the round | The original hash shown before play |
| Client seed | Adds the player's input to the calculation | The exact client seed recorded for that round |
| Nonce | Identifies the round within that seed sequence | The round's recorded nonce |
| Game and calculation rules | Convert the generated values into a game outcome | The matching game, algorithm and any additional event inputs |
Other implementations can use different inputs or reveal procedures. Follow the documentation for the particular game.
Verify a recorded round
- Before play
Keep the commitment
Record the server-seed hash, client seed and relevant round details. A result calculator can reproduce an outcome without establishing that the server committed to those inputs beforehand.
- After reveal
Compare the seed's hash
In Stake's implementation, rotating the server seed reveals the previous one. Hash that revealed seed with the documented method and compare it with the earlier commitment. Use the old seed associated with the round, rather than the replacement seed.
- Calculate
Reproduce the outcome
Select the exact game and enter the recorded server seed, client seed and nonce. Apply the documented game-specific conversion and compare the generated outcome with the round history.
The game selection matters
Stake documents HMAC-SHA256 output generated from the seed inputs, with a cursor used when a game needs additional output. Its game-event rules then map generated values into outcomes such as dice rolls, cards or mine positions. Matching the seeds while choosing the wrong game conversion cannot verify the recorded event.
Changing a client seed changes an input for future rounds. It does not reveal the hidden server seed or give you a winning prediction. A provider slot and a casino's own seed-based game may also use different systems; check whether the particular game offers this verification.
If your calculation differs
A matching round leaves other questions open
Matching the commitment and reproduced outcome supports the claim that this round followed the documented calculation with the committed inputs. It does not remove the game's house edge or turn a losing result into an error.
The calculation does not test withdrawal processing, account treatment or every game on the site. Judge those matters through their own evidence.
Continue with the question that matters
- House edge and expected results
- RTP and hit frequency measure different things
- My Stake account review
Account observations have a different scope from a game calculation.