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

f62545ca3baed3ee7785357c50c2ab5b6129059052b6113c87697d5a1a1dce51

Seed

47d588680a3139ded007536fe2f2c6a8b4bb36f3ca62685602952377ade8a473 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

017bcd616dbc5649b3c8f1045e00995d

Commitment

Batch 68,111, Merkle root 089643a2812888cd683e5af57583d9bbba98794e543081e2c29c0f41061242e9. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 40dd3e992064dca6929ebe6a8366290758b699c1a669686389293b394de94244
2. df56a44a392d99f5c79a4be7006668a3554a00374df20fa220992020bcde1f99
3. 7c366e329765057463d02ca1a21d4a5c6521be2bc716e0089b20667d35520146

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.