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

da12d01f461f22dbb178c45d268c9ef0542eea5bc2b8bc7b7488cb4fc221574a

Seed

3c8addaf8851d35535df882c59cc0ab53607917c5e05c7cbf9ab7e40e91d0c6d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

95290acab0f1a5ffaaefe9ad7dd5f806

Commitment

Batch 61,306, Merkle root 58ab500a27e6e785b6655b0fcd92e5891c1c152928f0898b9dabe08417885ec4. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 69287be15e56fe9b50be4602cf3e7a4871fa26d8166444d53cf0d29fcb3d2726
2. 64c02a2fb7d89f90ffd5c0596af0d1a19969d669f37bad13b11165d5706f0029

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.