Verify any round yourself

Before you can stake anything, the server rolls a secret 32-byte number and publishes its fingerprint (a SHA-256 hash). The fingerprint cannot be reversed, but it cannot be changed either. When the round ends we publish the secret. If the secret still produces the same fingerprint, we could not have altered the outcome after seeing your stake — and running the same formula on the secret gives you the exact multiplier the climbers fell at.

• Message — client_seed + ":" + nonce + ":" + round_id, encoded as UTF-8.
• Digest — HMAC-SHA256(key = server_seed, message), where the key is the 64-character lowercase hex seed string in UTF-8, not its decoded bytes.
• Uniform value — take the first 13 hex characters of the digest big-endian. That is an integer x uniformly distributed over [0, 2^52). No floating point is used.
• Multiplier — crash_bps = floor(8500 × 2^52 / (2^52 − x)). The 15% house edge is the single 8500 numerator (10000 − 1500); it is applied exactly once.
• Bounds — clamped once, at the end, to [10000, 100000000] basis points (1.00× to 10000.00×). The displayed multiplier is crash_bps / 10000.
• Commitment — SHA-256(server_seed) over the same UTF-8 hex string.

Nothing else touches the outcome: no clock, no client input, no database randomness, no post-commitment value. The round id is inside the message so an identical seed and nonce can never be replayed across rounds.

Every settled round publishes its full proof. Load one to check it without typing anything.

This release runs on demo credits only. The fairness commitment is a genuine cryptographic scheme rather than a decorative label, but it is not an audit, a certification, or evidence of regulatory approval.