Provably Fair Dice

Blockchain-style verifiable randomness. Every roll is cryptographically committed before you play — then revealed so you can verify fairness.

Committed Server Seed Hash (SHA-256)

Computing...

Client Seed (editable)

Verification Panel

Server Seed Hash (committed)

...

Server Seed (revealed after roll)

Roll to reveal...

Client Seed

player-seed-2025

Nonce

Seed Status

Server SeedLOCKED

Client SeedEDITABLE

Current Nonce0

Total Rolls0

Algorithm

hash = SHA-256(server_seed)

hmac = HMAC-SHA256(

key: server_seed,

msg: client_seed + ":" + nonce

)

result = parseInt(hmac[0:8], 16) % 6 + 1

Fairness Guarantees

Server commits to outcome before player input via hash pre-image

Player influences outcome via editable client seed

Auto-incrementing nonce prevents seed reuse

All cryptography uses Web Crypto API (SHA-256 + HMAC)

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