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

d5a9a10f8ab0aca74c52e4f7daed7273771d0124e4961e278c7dec027e46b9f0

Seed

5323ff3ea424fef4b3c711cc830bd9c8d2036561acac025a917448e3eb3d119d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

8762bf280be61cbf47d7b988333caf2c

Commitment

Batch 69,167, Merkle root 23b86b2da4b16b3f9063dd18d54ba9782582906b39f699f0846a1a4ffe172245. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 73857221961bad6a07ce5bd77711a98ba4ea6bc5c529dc7b396474f2b38db706
2. 852dedf7e08ce0b2700ad6f650699b1d1663a9c3d421c936ec1cd2a5519c708f
3. 53dec1e656e696f0966d933584a5cf97e814ff0dbca9e2ef6acc67e6b14e1450

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.