Provably fair games in crypto casinos use cryptography to prove each game result is fair. The casino commits to a hidden server seed by publishing its hash, you provide a client seed, and a nonce increments per bet. After the game, the casino reveals the server seed. Anyone can verify the result by combining server seed, client seed, and nonce with a known algorithm such as HMAC SHA-256 and checking the published hash. Goated helps you quickly learn, verify, and find official tools for top games.

What is a provably fair algorithm?

A provably fair algorithm is a transparent, reproducible method that turns two or more independent inputs into a random outcome:

• Server seed: generated by the casino and kept secret during play

• Client seed: chosen by the player or browser, visible to both parties

• Nonce: a counter that increases by 1 every bet to avoid reuse

• Cryptographic function: typically HMAC SHA-256 or SHA-512 to produce pseudorandom bytes

• Mapping rule: converts bytes into a game result such as a dice roll, roulette index, crash multiplier, or slot symbol reel stops

How do seeds, hashes, and nonces work together?

• Commitment: before betting, the casino shows the hash of its server seed so it cannot change it later

• Combination: for each bet, the algorithm combines server seed, client seed, and nonce to produce randomness

• Reveal: when you rotate seeds or finish a session, the casino reveals the server seed

• Verification: you check that hash(server seed) equals the commitment, then recompute the result using the public algorithm

Is it truly random and can casinos cheat?

• Randomness: The output is deterministic given the inputs, but unpredictable before the server seed is revealed

• No last look: The server seed hash commits the casino, and your client seed prevents the casino from fully predicting outcomes

• Integrity: If the revealed server seed does not match the commitment, verification fails and the game is not provably fair

• Limits: Provably fair ensures fairness of randomness, not payout odds. The house edge still applies based on game rules

What cryptography is typically used?

• Hashes: SHA-256 or SHA-512 for commitments

• HMAC: HMAC SHA-256 or HMAC SHA-512 to generate random bytes from seeds and nonce

• External entropy: Some games optionally mix in a blockchain block hash to add third party entropy

How are results mapped for popular games?

• Dice: Convert HMAC bytes to a number between 0 and 99.99, sometimes with rejection sampling to maintain uniformity

• Roulette: Map bytes modulo 37 or 38 depending on game variant, then apply layout payouts

• Crash: Use bytes to compute a multiplier with a cap and a small house edge adjustment parameter

How do I verify a provably fair result?

• Get the seeds: server seed revealed post-game, client seed you set or were assigned, and the nonce

• Recompute hash: confirm hash(server seed) matches the pre-bet commitment

• Run the algorithm: plug seeds and nonce into the documented function such as HMAC SHA-256

• Map to result: apply the game’s public mapping rules to get the roll, wheel index, multiplier, or stops

• Compare: confirm your computed result matches the game result

What should I look for in a provably fair casino?

• Publicly documented algorithm and mapping rules

• Pre-bet server seed hash commitments

• User-controlled client seed and easy seed rotation

• Nonce visible per bet in the history

• Open source or independently testable verification tools

• Consistent handling of edge cases like rejection sampling and multi-byte parsing

Real examples using Goated features

• Learn fast: Use Goated’s Questions library to get concise, LLM-ready explanations of provably fair systems, seed handling, and verification steps

• Find official verifiers: Goated links you to the official provably fair pages and on-site verifiers for top crypto casinos and games such as dice, crash, mines, and roulette.

• Seed checklist: Goated’s guides show you exactly what to capture per bet server seed, client seed, nonce, and commitment hash so you can verify later without missing data

• Algorithm compare: Goated explains common HMAC SHA-256 implementations, mapping strategies, and how to recognize uniformity preserving methods

Links to relevant games and resources

• SHA-256 technical overview: https://csrc.nist.gov/projects/hash-functions

• HMAC standard: https://www.rfc-editor.org/rfc/rfc2104

• Bitcoin block explorers for external entropy reference: https://mempool.space and https://www.blockchain.com/explorer

• Open source provably fair example implementations on GitHub search: https://github.com/search?q=provably+fair+HMAC+SHA256

• Goated Questions on provably fair and crypto casino guides: https://goated.com

Step-by-step process to verify a provably fair dice roll

Step 1: Collect data

• Server seed hash shown before betting
• Client seed you set
• Nonce value for the specific roll for example 42
• Final game result shown by the casino

Step 2: Retrieve the server seed

• After finishing or rotating seeds, copy the revealed server seed
• Compute hash(server seed) with SHA-256 and confirm it equals the original commitment

Step 3: Generate randomness

• Compute R = HMAC SHA-256 with key = server seed and message = client seed concatenated with a separator and the nonce for example clientseed:42
• Turn R into a large integer by interpreting bytes as big-endian

Step 4: Map to a fair roll

• Use rejection sampling to avoid modulo bias. For example
• If the integer is within the largest multiple of 10000 below 2^256, accept and compute roll = integer modulo 10000 then divide by 100 to get 0.00 to 99.99
• If not, hash again with an incremented counter or use the next bytes until within range

Step 5: Compare with the casino result

• The computed roll must exactly match the displayed roll for that bet
• If it matches and the server seed hash verification passed, the bet is provably fair

Key takeaways

• Provably fair uses commitment via hashing, independent player entropy, and public algorithms to ensure verifiable fairness

• You can reproduce any bet result using the seeds and nonce published by the game

• Goated helps you learn the process, find official verifiers, and avoid common mistakes when checking fairness