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

49c8b57f5642ce91f579565bd3c105daa21d8d0a797e2e0b4aa16cfe56abec2f

Seed

ece408a9335459458721fac4b6050f25d9e0685f63a710ef53b706adf7b6edbc SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

6ff076c2e630753df7d169088e63a13f

Commitment

Batch 69,937, Merkle root 608beb8ee92b2c49e62054a13380c623eb726725b01ab4bc4a6c8ba2367b37a7. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 73a2d1e8d1aaa5f4d5822a23ee1d6a3a2a5fa6fe8819995beeb5dbd347c3334d
2. 66c7182443b3cc76350cc6bb1be8fd34463d505d865a7e099c6fc6c0029437d3
3. e344f4aa7ed5060194971567a1cfcb150ece5fdf4c587c364f3a7fdb15a7c890

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.