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

d8fb15ce2312f4679b42299d95b2a6530b46cd22f15796ca1c91d3dfd1b63f9e

Seed

77fbf9438fdbd2caa82ab801a85ccfc20ec22bca6aa94a5d566150a58259b065 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4405b7dfedcc288268a85d40619d3632

Commitment

Batch 64,344, Merkle root 24ea85484f2144850180f059cf1efe60b100b1f55123eae78e8526a108945277. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. b2b8c4184b0cb45124d8952f9d71ccb5a2d1e4b31e91d2ce7bc0c22677e47267
2. a5a39e36ad8afe5575bc796f2dac370c44663a3a2d9785e0b00bac462504ac94

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.