Provably Fair

Provably fair is a method that lets players verify game results independently. Traditional online casinos ask you to trust that their games are fair. With provably fair, you do not have to trust anyone. You can check it yourself.
The system works through cryptographic algorithms. Before each game round, the outcome is already determined by a combination of seeds (random values). These seeds are hashed and committed before you place your bet. After the round ends, you get all the information needed to verify that the result matches the committed hash.
If anything was changed after you placed your bet, the verification would fail. Simple as that.

The provably fair system uses three main components:

• Server Seed. Generated by BC.Game before the game starts. You receive a hashed (encrypted) version before betting. The actual seed is revealed after the round so you can verify it;
• Client Seed. Generated by you or your browser. You can change it anytime. This seed ensures that BC.Game cannot predict or manipulate your results;
• Nonce. A number that increases with each bet. It makes every round unique even if the seeds stay the same.

These three elements combine to create a hash using the HMAC_SHA256 algorithm. The hash determines the game result. Since the server seed is committed before you bet and the client seed comes from you, neither side can manipulate the outcome.

After each round, you can verify the result:

1. BC.Game reveals the server seed that was used.
2. You already know your client seed and the nonce.
3. Combine them using the same algorithm.
4. If your calculated result matches the game result, the round was fair.

BC.Game provides built-in verification tools for all original games. You can also use third-party calculators or write your own script to check results. The algorithm is public and documented.

BC.Game offers several original games that use provably fair technology:

• Crash. A multiplier rises from 1x until it crashes. Cash out before the crash to win. The crash point is determined before the round starts using a pre-generated hash chain of 10 million values. You can verify any round;
• Limbo. Set a target multiplier and bet. If the generated result exceeds your target, you win. Results are calculated from the hash using a formula that converts it to a multiplier value;
• Plinko. Drop a ball through a pyramid of pegs. Each peg is a 50/50 left or right decision. The path is determined by dividing the hash into groups and converting each to a direction;
• Ultimate Dice. Roll a number between 0 and 10,000. Set your win condition (over or under a target). The result comes from converting 8 characters of the hash to an integer;
• Classic Dice, Wheel, Mines, Tower, Keno and other BC.Game originals also use provably fair algorithms. Each game has its own verification page with detailed explanations.

For Crash, BC.Game generated 10 million hashes in advance. These are released in reverse order, one per round. Each hash can be used to calculate the previous one using SHA256. This proves the entire chain existed before any games were played.
You can verify this yourself. Take any game hash, run it through SHA256, and you get the hash of the next round. If the chain checks out, no manipulation is possible.

Traditional casinos use random number generators that you cannot check. You trust their audits and licences. Provably fair removes that trust requirement.

With BC.Game:

• Results are determined before you bet;
• You influence outcomes through your client seed;
• Every round can be independently verified;
• The algorithms are public and documented;
• No one can manipulate results after bets are placed.

No. Most players never verify anything, and that is fine. The system exists for those who want transparency. Knowing that verification is possible keeps everyone honest.
The tools are there if you ever want to use them. Check a round that felt suspicious. Audit your session history. Or just trust the math and enjoy the games.

Each BC.Game original has a built-in verifier. Click on any past round to see the seeds and check the result. You can also find third-party verification tools on crypto gambling forums.
For technical details about specific games, visit the Fairness page for each game in the BC.Game menu.