Provably fair explained in four steps
Something that a casino promises to do before a game, and a player can verify after the game.
- The casino locks a secret
The server generates a number, a seed, and gives players a hash, or a fingerprint, of the seed.
- You add your own seed
A client seed, or a number of your choice, is provided by you. A counter called a nonce goes up by one with every bet.
- The result comes from all three
All seeds and the nonce are combined and havehed to determine the outcome of the game.
- The casino reveals the secret
The server seed is revealed. Using your verification tools, you can compare the server seed to the hash provided by the server to verify if the outcome of the game was altered.
Spribe's Aviator, or any other game of theirs, verifies in the same manner. The hashed server seed is provided to players before the game starts. After a game is completed, players can view the server seed, player seeds, hash, and the outcome.
Check a provably fair round yourself
Edit any field and the results update.
Winna utilizes the same procedure as described in the help center, generating a HMAC-SHA256 hash of the client seed, nonce and a cursor, using the server seed as the key. Each 4-byte value is interpreted as an unsigned integer from which a coin flip is determined. If that value is less than 0.5, the coin flip is heads. Winna’s blackjack game deals its first card from the second value. Using the seeds from the example, a nonce of 2 results in a coin flip of tails and the ♣2.
Alter the last digit of the server seed from 2 to 3. The new hash is b5d6177907480db2f05ba7879ffea4db4c8d0bfa871ce69b73ee32be773b6b27. As you can see, the new hash has no resemblance to the first. Thus, a casino cannot disclose their seed, alter it, and expect to keep using the same hash.
What provably fair does not prove
Four limits the marketing leaves out.
- The house edge is still there
This is hard coded in the game. Therefore, the house edge for Winna’s Coin Climber is 2%. Other games, such as BC.Game’s Crash, keep a house edge of 1%.
- It covers only some games
Most studio slots and all live dealer tables sit outside it; slots rely on RNGs tested by labs, and live tables on real cards and wheels. 1xBet's own 1xGames run on an RNG its terms describe.
- It says nothing about payouts
A fair coin flip does not mean the casino is legit or that it will pay out your withdrawals.
- It only works if someone checks
Change your client seed now and then so the old server seed is revealed, and test a few rounds.
We suggest using provably fair as just one of several ways to verify a crypto gambling site. For other methods, see our fake crypto casino and Lagos gaming licence guides.
Where you meet provably fair games
Casino originals, and one famous crash game.
BC.Game and Winna post their Provably Fair codes. Spribe's Aviator is a Provably Fair game and is offered by multiple casinos such as Bets.io and 22Bet. Our crash games guide explains how Provably Fair works against Aviator predictor apps.
What the law says
What the law saysSince a Supreme Court ruling of 22 November 2024, each state licenses gambling within its borders. Crypto is legal and regulated by the SEC. A casino licensed abroad is not licensed by any Nigerian state, and our reviews say which kind each casino is.
Check before you play
Check before you playLagos law makes promoting unlicensed gaming an offence, and the Lagos authority publishes a list of operators it calls illegal; none of them appear on this site. Check that playing is lawful where you live. Our guide is crypto gambling legal in Nigeria explains the rules.
Provably fair: common questions
The casino picks the server seed and displays its hash. Once you give your client seed and place a bet, the server combines the three and produces the result. The server reveals its seed and you can verify the hash and the result.
Once a hash is published, results cannot be changed. This is because the system is designed to work this way. Although, the house edge is guaranteed to be in the game outcome, making it so the game will always return less than the player bets over the long run. For example, Winna's Coin Climber code implements a 98% return.
No, it does not. Provably fair only ensures the game outcome is correct. You need to check other things such as if the casino is legit and licensed.
No, however, in order for this to protect you, you'd have to have some games checked. To do this, you'd have to change your client seed. The casino would then have to reveal the server seed for that time. You'd then have to have some of those games checked.
Fair games still cost money
A fair edge is still an edge.
Gambling is meant to be an entertainment activity, and if you feel like you are taking things too far, set a budget, and stop if you reach the limit.
If gambling is no longer fun or entertaining, find other activities to do. Talk to people about it if you have to.
Gamble Alert: +234 916 295 7989 (24/7), toll-free +234 705 889 0073. MANI: 0809 111 6264.
Free, confidential helplines. You must be 18 or older to gamble.