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

69bac6b17803d7555c6ca301065dcca4f6e84184191d6417806725b434b5fe98

Seed

28c5c995749712dde9733e27d219976ce6b0f4abf9fcd32bd250cb762556640f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

90c7a2a5e6c20715c2b60a6d9e9ec62d

Commitment

Batch 50,432, Merkle root e9c844b45949506ebcf9949255466bdc58b770e8ab9a1a9be5dcd7c44e420f28. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. d4707355abf1f81c6c37e5efdbb73981565e98ac72dab18d75369edbe1baca52
2. e78aad276f781b99c0beac450c9ff7d40be94f52292639d170cbb4447448f442

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.