Provably Fair

Every result on CherryBet can be checked independently — by you, in your browser, without trusting us.

How it works

Before you bet, the server picks a secret server seed and shows you its SHA-256 hash. You also have a client seed (which you can change) and a nonce that counts up by one with every bet, across all games.

Each result comes from HMAC-SHA256(serverSeed, clientSeed:nonce). Because the hash was committed before you bet, the server can't change the seed afterwards. When you rotate your seed (Dice page → "Rotate server seed"), the old one is revealed so you can check every bet it produced.

Verify a bet

Server seed (revealed)

Client seed

Nonce

Number of mines (only for checking a Mines round)

Server seed hash — compare with the hash you were shown before betting:

Dice roll

Coinflip

Roulette

Limbo crash

Plinko bucket

Keno draw (10 of 40)

Mines — mine tiles (1–25, row by row)

Blackjack — cards in dealing order (you, dealer, you, dealer, then as drawn)

Only the result for the game you actually played at that nonce is meaningful — the others are shown for convenience.

Verify a Crash round

Crash rounds are shared by everyone, so they use a hash chain instead of your own seeds. Before any round was played we published the chain's commitment and salt (below). After each round its hash is revealed. Hashing it with SHA-256 gives the previous round's hash, and hashing a round's hash as many times as its game number gives the commitment — so no result could have been changed afterwards.

Round hash (shown after the round crashes)

Salt

Game number in chain (optional)

Crash point

Chain check

Previous round's hash (sha256 of this one):

Published commitment:

Game formulas

Roll (0.00–99.99) = first 13 hex characters of the HMAC as an integer, mod 10000, ÷ 100.
Dice — win if the roll is over/under your target. Payout = (100 ÷ win chance) × 0.97.
Coinflip — roll < 50 is heads. Pays 1.94×.
Roulette — winning number = ⌊roll ÷ 100 × 37⌋ (European single-zero). Red/black pays 2×, a single number 36× — standard European odds, where the green zero gives the house its 2.7% edge.
Limbo — crash point = max(1.00, 97 ÷ (100 − roll)).
Plinko — each of the 16 bounces is one bit of the raw HMAC bytes (1 = right); the bucket is the number of right bounces.

Keno, Mines and Blackjack need more than one random number per bet, so they use a float stream: HMAC-SHA256(serverSeed, clientSeed:nonce:round) for round = 0, 1, 2… gives 32 bytes each, and every 4 bytes make one float in [0, 1) as b0/256 + b1/256² + b2/256³ + b3/256⁴.

Keno — the draw is a Fisher–Yates shuffle of 1–40: for each of the 10 draws, take the number at position ⌊float × numbers left⌋ out of the pool. Payouts depend on picks, hits and risk, at 96.5–97% return.
Mines — the same shuffle over tiles 0–24; the first m tiles drawn are the mines. Fixed when the round starts, so nothing you click can move them. Each gem pays the fair odds × 0.97.
Crash — HMAC-SHA256(key = round hash, message = salt); take the first 13 hex digits as h. If h is divisible by 33 the round crashes at 1.00×; otherwise crash = ⌊(100·2⁵² − h) ÷ (2⁵² − h)⌋ ÷ 100. The multiplier shown climbs as e^{0.00006 × ms}. About a 3% house edge.
Blackjack — card n of the round is ⌊float_n × 52⌋ (rank = value mod 13, suit = value ÷ 13), dealt you, dealer, you, dealer, then in the order cards are drawn. Blackjack pays 3:2, the dealer stands on all 17s.

Dice, Coinflip, Limbo, Plinko and Mines carry a 3% house edge, built into the payouts above. Roulette's 2.7% edge comes from the zero.