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

19417b0febe6dc2ea80d44e14ccb4929f7ef0bebd7879b54a75f94e61bfa2759

Seed

da4e7fdc680d7610ced664640a5e107e8e2e7ddf23a8d8f1efd2c577a6e875ca SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

565584183b0436c3e18a327d48851327

Commitment

Batch 49,611, Merkle root d30996ac601296a17cf4135e3c1e2a100d906c2fb00e62071c846d49d10fffb1. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 4693150432c535db9586f24010598ec2be4008931dab2c4a4a5dcaa652958b74
2. 58de708199b2825a0fa0efa7cf2da8794fc2e0eb8f25e75ec6b95fb4247db7fe

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.