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

d25ea215963304a0596b364817b021d4c75691ceffd2fed08511c84aed1040f4

Seed

040512dd080e52a71002a720592522441b89d051a56c1d419e663a6ad7821d36 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

982607c20a981dee7496dbf4fa854740

Commitment

Batch 60,391, Merkle root 84754b4e75e92bbae48234e5f229b1e42e7922ad12c57d1211cc2bdd71b1fe91. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. eb2efa8267059a182234f1dd91b176f6e36a1c41997f60f83f20d4da84e4e5f8
2. 3b8e16eac089a5b2fad4b1b5076a3afe9d7b2c0dc0e8ed3263fa7e1f0fbf223e

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.