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

04639a462ada086e5fb82a030953ecfcdf5ffb4e4db8676999c778254d67ff0a

Seed

414b742696d0905a3d98bbff18254c6ae8d7a9578f542ad5225f963069873acd SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

666f61268ebca9456816ba331799f1ea

Commitment

Batch 69,391, Merkle root 0777bc5334d4ec5db4d4136a8b470c7ef68c4c8df2475fcbbef5e951f403f4b4. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. b3a65a5f86d575a59014986baf7cefa5db2590d25c9217052c870124efc2ca92
2. ec98014aaaeaddb8b11d7a0a7c360e635d95705d55f791ab66cd0b0b1e7ee6f1

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.