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

80ccab63f68741a3eae4f63afbb6d731ba918daca0f7ff6a31622874439f126a

Seed

5681b93bd2031e78849828d1614464025673ef5d113e703eeb72a42d4c754e16 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

9be491fe2c3eb787d6cc8bd64f1be04d

Commitment

Batch 70,498, Merkle root 7bf667ead7fb19cebd67c00820543545302971ea32fe3bcbbcc10c9306d0b5d4. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. d3ae5ca1653ee94a97e0c8458d8cb7c2a9708f0af4aaa7d57501698abf3a0aa2
2. 6a33a9a47bd45ea2641da38ca75e733508f3918f58b7652de7bf27152671bf5d
3. 040c5b780e73e9017c3908337e4eee14f3b949a4dec086b718cf9dcfe2a9a633

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.