What Does Provably Fair Mean?

The whole idea rests on a one-way hash function such as SHA-256. Feed it any value and it returns a fixed-length string. Two properties matter here: the same input always produces the same output, and you cannot work backwards from the output to recover the input.

That combination allows a commitment. The casino generates a secret value, hashes it, and shows you the hash before you play. The hash reveals nothing useful about the secret, but it locks the casino in — publish a hash, and the only value that will ever match it is the one you already had. When the secret is revealed afterwards, you hash it yourself and compare. A match proves the value existed before the bet and was not swapped for a more convenient one.

Everything else in a provably fair system is plumbing around that single guarantee.

Most implementations use the same three inputs:

• Server seed — a secret random value generated by the casino or the game provider and kept hidden during play.
• Client seed — a value you supply, or one generated in your browser that you can change at any time.
• Nonce — a counter that increases with each round, so the same pair of seeds produces a different result every time.

The typical round follows a fixed sequence:

• The provider generates a server seed and publishes its hash before play begins.
• You set a client seed, or accept the default one offered.
• For each round, the game combines server seed, client seed and nonce and runs them through a deterministic formula to produce the outcome.
• After the round, or when you rotate to a new seed pair, the provider reveals the original server seed.
• You hash the revealed seed, confirm it matches the hash published earlier, then re-run the formula to reproduce the result.

The client seed is what stops the reverse problem. Because you contribute an input the operator did not know when it generated the server seed, the operator cannot pick a server seed that produces a convenient outcome for a bet it has not seen yet.

Here is one round, start to finish, in the order the values appear.

Suppose a crash round ends at 2.41x and you want to check it. The fairness panel showed a hash before the round. Afterwards it reveals the server seed. You paste that seed into any SHA-256 tool and compare the output with the hash you noted — they match, so the seed was not substituted. You then feed the server seed, your client seed and the round's nonce into the provider's published formula and get 2.41x back. The round is verified.

Note what happens if the operator had tried to cheat. Changing the outcome would require a different server seed, which would hash to a different fingerprint, which would not match what was published. The mismatch is immediate and undeniable, which is precisely the point.

Studios apply the same principle with their own naming. According to BGaming's published workflow, the game outcome, called the Result, is calculated before the bet is placed, paired with a random Secret, and committed using a SHA-256 hash. Players can set a Client Seed, which is then applied to the precomputed Result to derive the Final Result shown in the game. Once the round completes, the provider reveals the Result and the Secret so players can verify the commitment and confirm the final outcome was derived correctly.

The moving parts map directly onto the general pattern:

• Result plus Secret — the precomputed outcome and a random string, hidden during play
• Hash(Result + Secret) — the commitment displayed before gameplay begins
• Client Seed — the player-controlled input applied to the precomputed result
• Final Result — what the game displays, derived from the disclosed inputs
• Post-round disclosure — the reveal that lets a player audit the round independently

BGaming applies this across several game types, including roulette, card games, video poker and some slots. In a roulette round the game pre-generates an outcome and a secret, publishes the hash before the spin, and reveals both afterwards so the player can confirm the displayed number came from the disclosed inputs. You can read more about the studio in our BGaming provider guide.

Both approaches aim at the same thing and answer to different auditors.

Neither replaces the other. Certification tests the statistical quality of the randomness across a whole game; provable fairness tests the integrity of one round you actually played. Our guide to random number generators covers the certified side in detail.

• Myth: provably fair means you are more likely to win. Reality: it verifies integrity, not generosity. The house edge is written into the paytable and is untouched by verification.
• Myth: the casino cannot see the result before you do. Reality: in most implementations it precomputes the result. What it cannot do is change that result once the hash is published.
• Myth: a provably fair label is proof on its own. Reality: the proof is the verification you run. A fairness panel that never reveals a server seed, or a provider that does not publish its formula, gives you a label and nothing to check.
• Myth: verification requires programming skills. Reality: most providers include a verify button, and any public SHA-256 tool will confirm a hash match in seconds.
• Myth: changing your client seed improves your odds. Reality: it changes the outcomes produced, not their distribution. Rotating the seed is a fairness habit, not a strategy.

• What is an RNG — how certified randomness works in standard casino games
• What is a crypto casino — the environment where provably fair games are most common
• Are crypto casinos safe — the wider checks that sit alongside game fairness
• Casino glossary — plain definitions for hash, seed, nonce, RNG and RTP

Provably fair technology is used primarily in crypto casino games and lets players independently verify that results were not manipulated by the casino or the player, using cryptographic algorithms that can be checked mathematically after a round has ended. Not every casino game uses it: it appears where a provider has built the seed and hash workflow into the game, and it sits alongside — rather than instead of — the tested random number generators behind the rest of the library.

At Lunaris the casino library runs on games supplied by established studios, and the fairness model depends on the title you open. Where a game includes a provably fair panel, the seeds and hashes are shown in the game interface itself, so verification happens there rather than through the casino. You can see which studios are live on the providers page, and each studio publishes its own fairness documentation.

For everything else, fairness rests on independently tested randomness for RNG games and on real dealers running real equipment in live dealer games. In all three cases the outcome of any single round is random and the game's long-run return is a mathematical average, not a promise about your session. If you ever want a specific round reviewed, contact [email protected] with the round number, bet amount, date and time, game and provider.