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

9ddccca0704ee9a1dd8aa628d6292e774f43ac7ed256468cfe7fc46779abfa4a

Seed

e2903f569fd410a34d1ddab0339f86b621c31528aa2ba0fb046ce1fa9db0a68f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b09ffde87089330038c39c4f4f579fec

Commitment

Batch 68,209, Merkle root 8b7b000a5924aad3f4ddece7d45582c8f5e68e8ea1550c34d8d89b3e27c3ecc4. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 93da02e45a967559ba4acd62f6b23cb686581b06194c57e568c3820d8a27acce
2. 0c3dceb4bf4ace8dce8996434e70f480247480de32cfa1752f0c9b15537785e2
3. 34119710fa9a87c7bbcac5abb59363c1178f6a0db0873c209211e95ee32dd488

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.