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

95e88aa541afff6cb228ed6ef565f118919abcd51cd2255a510e48db981094e4

Seed

e316a0ade0e092ef9f3193d8f970c3b857ccb7838c97618bf7429ec88017172e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

9d7987e69939f807bd6403e4ba785c18

Commitment

Batch 59,769, Merkle root be40c212572afc81ea9d0e0a8b7b52e544213011706c6662012f4145e05a81b8. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 5f50a1bc0a5ae903d417527d4a8ab342a6d6df8ddafe417a6e53ea4814843e5a
2. 1eca3d971e469356e6ae6ff0426424871e796c81480187af8ac05967c826b0e7

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.