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

9a3aa619f16aa91f092feb37ab2cfe1e01df00530e7cfafa4e4e43bbef1a9e38

Seed

a8577a9cb0e77611b201d1d0dc1fd8a98fa8a4dbbc498981af1285a02b0c6626 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4cf1d3f6241ae950186b8d21d6b71c76

Commitment

Batch 49,692, Merkle root e0bde6db9b05d412ff32f4c26e566431ccbf724da196737f41ca123ee48a0d12. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. bcb20ed4347079ef066612bf0e8ed7b12daa7cad43f48d776a5e8d4f6f6125e4
2. 06d31250ade5058f54ee1da29efdd5a56836e75e8af55824da3c8f599be2570c
3. 371b5e5f134ca10eefaf1f318f3bf584d7f2345786e7f4253ca540eae3ca6bc3

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.