- A provably fair game lets you check each result with three inputs: the casino’s server seed, your client seed and a bet counter called the nonce.
- The casino shows you a hash of its seed before you bet. It can’t swap the seed later without the hash changing.
- Bets at most crypto casinos are not stored on a blockchain. A block explorer can prove your deposits and withdrawals. It can’t check a game result.
- Seed checks cover in-house games such as dice and crash. Slots and live tables from outside studios use lab-certified random number generators instead.
Crypto fans like to say the blockchain is the future. Traders aren’t the only ones who listened. Online casinos added Bitcoin and other coins to their cashiers, and many now sell themselves as provably fair crypto casinos: sites where you can check a game result yourself instead of taking the casino’s word for it.
What makes a casino a crypto casino
Crypto casinos like PUBS casino carry the games people link with high-end gambling: slots, roulette, blackjack and live dealer tables. The difference is the cashier. Players deposit and withdraw in crypto. Many sites also offer in-house games built around a fairness check. PUBS lists more than 4,000 slots, a sportsbook and 26 in-house “Originals” such as dice, crash and mines.
Many crypto casino players started out as traders. They want what traders want from an exchange: proof that the numbers are real.
What happens when you deposit crypto
A crypto deposit starts in your wallet. Your crypto wallet builds a transaction to the casino’s deposit address, and nothing moves until you approve it. That approval is a digital signature made with your private key. It proves you agreed to the payment.
Your wallet then sends the signed transaction to the network. Nodes check the signature and your balance, and the transaction goes into a block. Bitcoin adds a new block about every 10 minutes. Tron and Solana confirm a stablecoin transfer in under a minute.
But at most crypto casinos, the blockchain records only the money going in and out. Your bets sit in the casino’s own database, the same as at a casino that takes cards. A few casinos run every bet through a smart contract. On those sites the bet and the payout also appear on the chain.
How provably fair crypto casinos let you check a result
Provably fair games solve the trust problem without putting each bet on a blockchain. They use cryptographic hashes, the same kind of maths that links the blocks of a blockchain. Casinos that offer seed checks use much the same five steps:
- Before you bet, the casino picks a secret server seed and shows you its SHA-256 hash. A hash works like a sealed envelope. You can’t read the seed from it, and the casino can’t change the seed without the hash changing too.
- You set a client seed, or accept the random one the casino fills in. Type any text you like, so the casino could not have picked its seed to suit yours.
- A counter called the nonce goes up by one with every bet you place on that seed pair.
- The usual formula feeds the server seed, the client seed and the nonce into HMAC-SHA256. The game converts the output into a dice roll, a crash point or a card.
- After you play, rotate your seed pair in the fairness settings, and the casino reveals the old server seed. Hash it with any SHA-256 tool and compare the result with the hash you saw before you played. If the two match, run the casino’s published formula, or an independent verifier, for each nonce. The results must match your bet history.
Expert tip: Copy the server seed hash and your client seed before your first bet. A record made before you play is the only proof that the casino showed you that hash.
What a provably fair check does not prove
A seed check proves the casino did not change a result after you bet. It does not cover slots or live dealer tables from outside studios. Those games use random number generators that testing labs certify, and you can’t check a single spin yourself.
A seed check also says nothing about whether the casino will pay your withdrawal. That depends on the casino’s licence and terms. Casinos hold coins in hot wallets that can be hacked: Stake lost about $41 million that way in September 2023, though it reopened withdrawals within hours.
We could not open the PUBS fairness settings without an account. Before you deposit at any casino, find its fairness page and check that it shows the server seed hash before your first bet.
How to verify a crypto deposit or withdrawal
For your payments, the only tool you need is a block explorer. It’s a search engine for one blockchain: paste in an address or a transaction ID, and it shows what the network recorded. Common explorers are mempool.space for Bitcoin, Etherscan for Ethereum, Tronscan for Tron and Solscan for Solana.
- Copy the transaction hash (TXID) from your wallet or from the casino’s transaction history.
- Paste it into an explorer for the same network. A USDT transfer on Tron won’t show up on Etherscan.
- Check the receiving address, the amount, the time and the number of confirmations.
- For a withdrawal, compare the amount that arrived with the amount in the casino’s history, less the network fee.
This proves the casino received your deposit and sent your withdrawal. It can’t tell you whether a hand of blackjack was fair. For that, you need the server seed, the client seed and the nonce.
Are crypto casinos the future of online gambling?
Speed is the strongest case for crypto casinos. A card withdrawal from an online casino can take several days. A crypto withdrawal settles soon after the casino approves it. That’s under a minute on Tron or Solana, and about an hour on Bitcoin if you wait for the six confirmations many services treat as final.
Privacy is the second selling point, though it has limits. Licensed casinos can ask for ID before large withdrawals, and anyone can trace a blockchain payment. Some fans also see crypto casinos as part of Web3, the idea of an internet built on blockchains.
Price swings are the main case against. If you deposit Bitcoin and it falls 10% while you play, you can lose money on a winning night. Many of these casinos answer this with stablecoins such as USDT and USDC, which track the US dollar. PUBS, for example, lets players show their balance in USDT. A stablecoin removes the price risk, but you take on the risk of the company that issues it.
The law is another limit. Australia, for example, has banned crypto payments for online wagering. Check the rules where you live before you deposit anywhere.
5 Frequently Asked Questions
What does provably fair mean at a crypto casino?
It means you can recompute each game result from the casino’s server seed, your client seed and the nonce. The casino shows a hash of its server seed before you bet, so it can’t change the seed afterwards.
Can a block explorer verify a casino game result?
Only at casinos that run bets through a smart contract. At most crypto casinos the explorer shows your deposits and withdrawals, and the bets stay in the casino’s own records.
Are slots at crypto casinos provably fair?
Usually not. Slots and live tables come from outside studios that use random number generators certified by testing labs. Seed checks apply to the casino’s in-house games, such as dice, crash, mines and Plinko.
Who licenses PUBS casino?
The PUBS website says the Tobique Gaming Commission licenses it under number 0000087. RegalTech Solutions Limitada of Costa Rica owns the site, and Petillant Solutions Ltd of Cyprus is its payment agent.
Why do crypto casinos use stablecoins?
A stablecoin such as USDT holds its value against the US dollar. Your balance doesn’t rise or fall with the price of Bitcoin while you play.
The Bottom Line
A provably fair game lets you recompute a result from the server seed, your client seed and the nonce. That check is the only proof that the casino didn’t change a game after your bet. A block explorer only proves that your deposits and withdrawals moved. Save the seed hash before your first bet. After you rotate the seeds, check a few results against your bet history. And set a budget you can afford to lose before you deposit, at PUBS or anywhere else.
Related Reading
Crypto casinos
Wallets and keys
Blockchain basics
Gambling rules
