Blackjack

Provably fair

Verify fairness

The session's seed decides every card. Its hash was committed before the first hand; the seed is revealed when the session ends. Each round's cards come from HMAC-SHA256 keyed by the seed over the round's number and the bettor's own seed.

Seed hash

b5c6cd929a0fd3e2fe004905c9d49bc118cd948caf0d7be54e5e0551a5e57f94

Seed

811d7514e4bcb89f66997e7fe332f2ec049686e7a4669469e0bf10c6da93aac2 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

d41b5f3322ec950c53ced74ca7052073

Commitment

Batch 66,442, Merkle root 89171bb53ef6d25b208ffe80af0e36c0b97981d2cb334a2273df7569fa72261e. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 085f9745a73875103cda578f1c3f4d5cb64e5d0f959f0adaea7a1162fdc6cf14
2. 5ee396c9656605788ee69b0dcd61f98761ba030e9cf68d7aaa2b7e7f8b0aa237
3. b1dd13f3b4434fdba7add121b80b820219e4a434da35f83f9c4ce78e48577275

Checked: the seed hash proves into the root.

To check it yourself, take the session's proof:

1. Hash the seed as above and compare it with the seed hash; prove the seed hash into the root with the Merkle path (keccak256, as for every match).
2. For each round: round seed = HMAC-SHA256(key = seed, "degen.house.round.v1" ‖ 0x00 ‖ u64be(length of the bettor's seed) ‖ bettor's seed ‖ u64be(round)).
3. Key ChaCha20 (RFC 8439, zero nonce) with the round seed and read little-endian 64-bit words; a card is the next word below 2⁶⁴ − 1 − ((2⁶⁴ − 1) mod 52), modulo 52.
4. Replay the round's actions with the game's rules: the cards and the payout must match.

The replay plays every hand rebuilt this way on the server from the same data, and marks any that does not rebuild as recorded.