Proof and reach
A real proof with a very narrow reach
Server seed, client seed and nonce produce a proof you can recalculate yourself — it tells you everything about the round and nothing about whether you will be paid at the end.
The only promise you can recalculate
In this trade a great deal is claimed and little evidenced. “Provably fair” is the exception: an undertaking you do not have to believe but can check yourself with a calculator and a hash tool in the browser.
What that proof precisely does not say about the payout is placed in context on crypto casino Austria.
Which is exactly why it is worth looking very closely at what is actually being proved. The proof is real. It is only far narrower than the label suggests — and the last section of this page is the most important one.
The problem that gets solved
A game online needs randomness, and the randomness comes from a computer the house owns. Without further precautions you face an imposition: you are supposed to trust that the number deciding your stake was not drawn after the stake was known.
Provably fair solves that with an order of events. The house commits itself before it knows what you will do — and it commits in a way that stops it later denying what it committed to.
The three numbers
The server seed. A long random string the operator generates and keeps secret. From it comes, later, the number that decides your stake.
The hash of the server seed. Before the first round the operator shows you not the seed but its hash: the result of a one-way function, as a rule SHA-256, displayed as a sixty-four-character hexadecimal string. Two properties make it useful. The seed itself cannot be reconstructed from that hash — which is exactly why it stays secret until the reveal. And the same seed always gives the same hash, while the smallest change gives a completely different one — which is why the hash is a commitment the operator is bound by.
The client seed. Your string. The operator proposes one, you can change it, and many explanations advise you to. The reason is the order: if you set the client seed after the hash of the server seed has been published, the operator can no longer pick its seed to suit yours.
The nonce. A counter. First round 1×, second round 2×, third 3×. It makes sure the same pair of seeds gives a different result in every round without the seeds having to be swapped.
The result of the round comes from sending the server seed, the client seed and the nonce together through a hash function. The resulting string is translated by a published rule into a number — in dice into a number of pips, in cards into a position in the shuffled deck.
The reveal
While the server seed is secret you can recalculate nothing — all you have is its hash. So a change belongs to the method.
You request a new server seed, or the house changes it itself. At that moment the old seed is disclosed, and at the same time you get the hash of the new one. Every round run under the old seed thereby becomes checkable, and every future one is committed in advance again.
Most players never change the seed and therefore never check. Without the change the method stays a claim like any other.
The order is the whole argument: the hash of the server seed is fixed before the round, your client seed comes after it, and the seed itself is revealed only at the change. If its hash matches the one published in advance, the result was settled before your stake. About the payout it says nothing.
How to check a round yourself
Six steps, in this order.
First: before playing, note down the published hash of the server seed. Copy it somewhere you will not lose it. Without that note there is nothing to check later.
Second: set your own client seed. Anything you have memorised or written down.
Third: play your rounds and, for the round you want to check, note the nonce. It usually stands in the round history beside the result.
Fourth: change the server seed. Now the operator shows you the old one in plain text.
Fifth: check the commitment. Send the disclosed seed through SHA-256 and compare the result with the hash from step one. If the two match, it is proved: it is the same seed the house committed to before your first round. If they do not match, that is not room for interpretation, it is a contradiction.
Sixth: recalculate the result. Put server seed, client seed and nonce together by the operator's published rule, hash them, and translate the result by the same rule into the pips or the card. If what comes out is what you saw, the round is confirmed.
For steps five and six you need no program of the operator's. Any SHA-256 tool will do, and if a house demands you use its own checking form, you have already lost half the independence of the proof. The rule for step six has to be published by the operator — if it is not, the method cannot be checked, whatever the page says.
What the proof covers
It shows that the result of a single round was settled before you staked, and that it was not altered afterwards. That is a lot: it rules out exactly the manipulation a house is most readily suspected of.
It also shows that your client seed goes into the calculation — set after the house committed itself.
What it does not cover — the real point
Here the reach stops, and this is the message of the page.
It says nothing about the return to player. A game can be fully checkable and still have a poor rate. The proof concerns the honesty of the draw, not the generosity of the rules.
It says nothing about games from other studios. Slots and live tables almost always come not from the house but from suppliers whose random generator the house does not own at all. For those games the method does not exist. Where it is offered, it typically concerns the house's own games — dice, crash, mines, cards — and thus a small part of a catalogue made of thousands of other titles.
It says nothing about whether you will be paid. That is the most important sentence on this page. A house can run every round provably cleanly and still delay your withdrawal request, cut it, or refuse it on the strength of a clause of its own. The draw and the payout are two separate events, and only the first is proved here. What governs the second is set out under withdrawal.
It does not replace checking the operator. Who stands behind the brand, under what supervision the house works and what its terms say are questions a hexadecimal string answers none of. They belong on another sheet — see reputable operators.
The register entry first, then the holder of the company. After that the withdrawal rules and the limits, and last the support desk and the complaint history. The order follows effort and discriminating power: the first two together take a few minutes and sort out the larger part.
It does not replace reading the withdrawal rules. The processing window, the weekly cap, the open wagering requirement: none of that gets hashed. How long it really takes, and why that has little to do with the advertised span, is set out under instant payout.
How to place the label
A house offering such a method has made itself checkable voluntarily — for a part of its offer. That is a point in its favour, but a small one, and it cannot be set off against figures missing elsewhere.
So check three things before giving the label weight. Is the calculation rule published, so that you can recalculate without the house's own tool? Can the server seed be changed at any time, or do you have to ask? And which games does it cover at all — the house's own, or supposedly all of them, which is technically impossible?
Anyone who wants to see how this question is placed beside the other checking points will find it under methodology and in overview under online casino Austria. The whole checking structure at a glance is on the list of crypto casinos for Austria.