Understanding provably fair on Stake

A blackjack card, a mine or a Dragon Tower tile: provably fair lets you retrace how a result was calculated after the game. Use the round’s data to check that the recalculated result matches the one in your history.

The sealed-envelope idea

Imagine Stake puts a secret number in an envelope and shows you its fingerprint. You add your own number, then each game receives a number too. Together, these elements are used to calculate the result.

When the envelope opens, you can check its fingerprint and run the calculation again. The secret number is the server seed, your contribution the client seed, the game number the nonce and the fingerprint the hash.

Find your game’s data

Open your history or bet details. Note the game, client seed, nonce and hash of the server seed used. These values identify the exact round you want to check.

The full server seed remains hidden while the seed pair is active. Use the rotate or replace seeds option to reveal the old one. You can then check the games played with that pair.

Run the calculation again

In the provably fair verifier, choose the game and enter the round’s data: revealed server seed, client seed and nonce, plus any requested settings.

The check involves two comparisons:

1. The revealed server seed’s hash must match the fingerprint published before the bet.
2. The recalculated result must match the one in your history.

Different result? Copy the values again from the same round. A different nonce, reversed seeds or another game version is enough to change the calculation.

What you have just checked

A match shows that the result follows the data committed for that game. The hash also makes it possible to detect a server seed replaced after the bet.

This check concerns a completed game. It does not reveal upcoming cards or tiles while the server seed remains secret, and it does not change the game’s probabilities.

A closer look: how data becomes a result

Server seed and client seed

Stake generates the server seed and publishes its hash first. The browser may generate the client seed at registration; the interface generally lets you change it. The calculation therefore combines server data with a player contribution.

Nonce

The nonce advances with each bet made using the same seed pair. It distinguishes consecutive games even when both seeds remain unchanged.

Hash and HMAC-SHA256

A hash turns data into a fixed-length fingerprint. Changing the data changes that fingerprint. Stake uses HMAC-SHA256 to combine the server seed, client seed, nonce and, when a game needs more values, a cursor.

The calculation produces bytes, converted into numbers between 0 and 1. Each game then uses them in its own way: mine positions, cards or other events. The same data and method produce the same result — which is what makes verification possible.

The game-specific conversion matters as much as the seeds. The verifier must therefore match the game and its version.

Frequently asked questions

Why wait for the server seed to be revealed?

Revealing it while still in use would allow upcoming results to be calculated. Stake shows its hash first, then the full seed after rotation.

Does changing the client seed improve my chances?

No. It changes the calculation inputs without changing the game’s probabilities.

Can I check several games with the same server seed?

Yes, if they were played with that seed pair. Use each bet’s nonce to retrieve its result.