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

5d5874cc80865447fae83ad7b3462f70275212744508184e89ce1f76eeee6923

Seed

291cc0a40d550193bee9ef2a054d40c4ce85a70083358a1a83a0dce1b83b6eb0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

33f04bda3ace66c956cb1a2f8e9fddb1

Commitment

Batch 66,908, Merkle root 3adffa37e08dfd7a92f75a367770c7b644a63b95315f6d1b4dc21ebea5e452bf. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 9833ee232e26e4a6f68223cb3cf41f6d8dd33f4e04a2e3d5b40d637e7920b52d
2. 0d30c1fc9008a768f74b7b6e105df0e6fa8402a687263b46ac19b38763e95185

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.