Crash
Single-player Crash on a 1,000-game SHA-256 hash chain built in your browser. Watch the curve, cash out before it crashes, verify every round. Play money.
Multiplier over time: it doubles every 2.5 s and stops at the crash point fixed by the game hash. Cash out before it does.
- Public client seed
- plinkolab-crash-public-seed-v1
- Chain head (game 1)
- building…
- Last game hash
- none yet — the head commits to game 1
- Games left in chain
- — of 1000
See the maths
The chain. On your first visit the browser draws 32 random bytes (the terminating seed) and hashes them forward 1000 times with SHA-256. Games are played in reverse: game 1 uses the last hash, game 2 the one before it, and so on. Because SHA-256(hash of game k) = hash of game k−1, the hash you were shown after the previous round is a commitment to the round you are about to play. Nothing can pick a different outcome after the bet.
The result. h = HMAC-SHA256(key = game hash, msg = "plinkolab-crash-public-seed-v1"); X = the first 52 bits of h as a fraction of 252; crash = max(1, floor(99 / (1 − X)) / 100). The 99 is the 1% edge: P(crash ≥ x) ≈ 0.99 / x, so a cash-out at x× pays x and wins 0.99/x of the time, whatever x you choose. About 1 round in 100 crashes at 1.00× instantly.
Check it. Every round shows its game hash. VerifyRoll recomputes the crash point from the game hash and this public client seed, and you can check that SHA-256 of any game hash equals the previous one (any SHA-256 tool will do). Here the client seed is a fixed public string; a casino uses a Bitcoin block hash mined after the chain was published, so that not even the operator could pick a favourable chain.
Play money only. Nothing to buy, nothing to win, nothing leaves your browser. Reset the balance whenever you like.