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

d5083d7e30107c5ac2c11bb8226433300ff5364dddf6b146623f6204a16339a9

Seed

c95c5fec49c0fa82e4e19df5bf0f0d248c8eb751f9ca6d394be9a64963b6e886 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

bcd02f17fa72e795e230b11ee6ae5870

Commitment

Batch 68,686, Merkle root b93d8aa129dd7ce2fb50ef9490f4e984fd9d145736f9c16a64f8a94ddb8e3283. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 83d22e362219f27f7b4f03b467fdb6f56226e8433034d4cd998b6a7dc479b610
2. 2c77b57b100e125c88274ce49a208c8b7a73075ce1a7bffae84f8772c55f734b
3. c2cbad6e8b8b19e3e11264fbe48db2be94cf7f7ec81e40014890b87dd5f649c2

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.