How A PvP Crypto Coin Flip Works: Original, Step By Step
Original is Cryptoflip's player-versus-player coin flip. Two people put up the same wager, one coin decides it, and the winner takes the pot. The interesting parts are how the result is drawn and why neither player, nor the site, can steer it.
Two players, one pot
You either create a game, choosing blue or red and a wager, or join a game someone else has opened, which puts you on the other side for the same amount. Once both sides are in, the flip runs and the game settles straight away.
The winner takes the pot minus 5%
The house takes 5% of the total pot from the winner's payout, and nothing extra from the loser. Two wagers of 10 make a pot of 20, and the winner receives 19. Over many games that cut is the whole of the house edge: a fair 50/50 that returns 1.9 times the stake costs, on average, 5% of each wager.
The server seed is fixed before anyone joins
When a game is created, Cryptoflip generates a secret server seed and shows its SHA-256 hash straight away. The hash commits the site to that seed without revealing it, so it cannot be swapped once bets are in.
Both accounts are part of the result
The result hashes four things: the server seed, a client seed generated when the game is matched, a nonce, and both players' account IDs. Including the two accounts means the outcome was not decided before your opponent joined, and a different opponent would have produced a different flip.
How a hash becomes blue or red
The four inputs are joined into one string and hashed with SHA-256. The first eight characters of the hash are read as a number and scaled to a value between 0 and 1. Below 0.5 is blue; 0.5 and above is red.
Sometimes your opponent is the house
Cryptoflip runs its own accounts that chat and fill games when the lobby is quiet, and you can also call the house account into your own open game. When one of them is your opponent, the wager settles against the house rather than another player. The maths, the cut and the verification are identical.
Checking a game afterwards
Every settled game keeps its server seed, client seed, nonce and participants. Open it from your history and the verifier on the Provably Fair page recomputes the hash in your browser, so you can confirm the side you were shown is the side those inputs produce.
Original is as simple as a coin flip gets, with the fairness made checkable rather than promised. Read the provably fair page for the full formula, or open the lobby and look at the hash before your first game.
Ready to play? Try Original or the Wheel on Cryptoflip.