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

4be2b25745bb9baa40b28498febff2969b36ea1ab3abe28df8b1ae62a40a6c59

Seed

bdab50c910e365fc561f73e67f153580f1ced3edee13b478c1f9b6768d35c41b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

615acda369552d2516ebcf8a9b95b32f

Commitment

Batch 62,695, Merkle root ba9b1fcddf3a983fe4dbb0ade143432c9419c3f64b4c2ef948e803fa5ede5e84. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f501e51051397cf94f5eaa608bdca6c21460aa137679132ba4e5024b64deae75

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.