Provably Fair at Dicey: How to Verify a Bet Yourself
Most online casinos ask you to trust a random number generator you cannot see, certified by a laboratory whose report you will never read. Dicey publishes a different arrangement for its in-house games: provable fairness, where the result of every bet can be recalculated by you afterwards. This page explains how it works and how to actually check it, because a claim you cannot verify is just a claim.
The Three Inputs
Every provably fair result is produced from three values, and the design matters as much as the maths: one value belongs to the casino, one to you, and one counts the bets.
| Input | Who controls it | What it does |
|---|---|---|
| Server seed | The casino | A secret random string. You are shown its hash before play, so it cannot be changed afterwards without the hash no longer matching. |
| Client seed | You | Your own input, random or chosen. The casino cannot predict or control it. |
| Nonce | The system | A counter that increases with every bet, so repeated seeds still produce different results. |
The three are combined with HMAC-SHA256 — a standard cryptographic function — to produce the number that becomes your result. Nothing about that step is proprietary, which is the point: anyone can reproduce it.
The Four Steps, in Order
- The casino commits. A server seed is generated and its hash is published to you before the game begins. Publishing the hash first is what removes the possibility of changing the seed later.
- You contribute. You accept a random client seed or type your own, adding input the operator does not control.
- The game runs. Each bet computes HMAC-SHA256 over the server seed, your client seed and the nonce, and converts the output into the outcome.
- You verify. When you rotate the session, the actual server seed is revealed. You confirm it hashes to the value published in step one, then recalculate any result from the session yourself.
Why This Is Different From a Certified RNG
A certified RNG is audited: a laboratory such as GLI or eCOGRA tests the generator, confirms the payout matches the declared figure, and issues a certificate for that build. It is a real safeguard, but it is a statement about the software in general, not about your spin. You are still trusting the certificate.
Provable fairness makes a narrower but sharper claim: it does not tell you the house edge is small — the edge is unchanged and built into the payout table — but it lets you prove that a specific result was not altered after you placed the bet. Two different assurances, and the distinction is worth holding on to when a site advertises one as if it were the other.
Which Games It Covers
Provable fairness applies to the operator's own titles — the "Originals" set including Dice, Mines, Plinko, Limbo, Keno, Coinflip, Black Holes, Dig Dig and Throne Tower. Third-party slots from outside studios do not work this way: they run on the studio's own certified RNG, because the maths lives in the studio's build rather than on the casino's server. That is not a flaw in either system, but it does mean the verification described here is available on some games and not others — worth knowing before you go looking for a verify button that a slot will never have.
How to Verify a Bet in Practice
- Note the server seed hash shown for your current session before you play.
- Play as normal; the nonce advances with each bet.
- Rotate the session, which reveals the plain server seed.
- Hash the revealed seed with SHA-256 and confirm it matches the hash from step one. If it does not, nothing else matters — stop there.
- Recompute HMAC-SHA256 over the seeds and the nonce for the bet you want to check, and compare the derived result with what the game showed. Any independent tool or a few lines of code will do this; you do not need the casino's own verifier.
Doing this once is worth more than reading any review, including ours. If the numbers reconcile, you have proof rather than reassurance — and if they do not, you have evidence rather than a suspicion.
Frequently Asked Questions
What is provably fair gambling?
A system where each bet's outcome is derived from a server seed, your client seed and a nonce through HMAC-SHA256, with the server seed hash published in advance so the result can be recalculated and verified after the fact.
Does provably fair mean better odds?
No. The house edge is unchanged and comes from the payout table. Provable fairness proves the result was not tampered with; it does not make the game more generous.
Which Dicey games are provably fair?
The in-house Originals — Dice, Mines, Plinko, Limbo, Keno, Coinflip, Black Holes, Dig Dig and Throne Tower. Third-party slots use the studio's certified RNG instead.
Do I need the casino's tool to verify?
No, and that is the strength of it. SHA-256 and HMAC-SHA256 are standard, so any independent verifier or a short script can reproduce the calculation from the revealed seed, your client seed and the nonce.
What if the revealed seed does not match the hash?
Then the commitment was broken and no further checking is needed — that mismatch is exactly the evidence the system exists to produce. Keep the hash, the seeds and the nonce, since together they are a reproducible record rather than an accusation.