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

413673062db2bf1e581fe7ceb2ce1f7ecd29bd133d3e6f7f34837ec10a7ef27e

Seed

595bab14030bb3b21e52da61625c3a7cac248ae605c6bcfaae5f49f2295e9cd6 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fe8d084ee3168590ae4e48173479ade8

Commitment

Batch 70,638, Merkle root 295ce16c5be65c01fd567e4a08be490e2f2602ac96e9a7afe1dc9f7100fd20f4. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. bf71df11732e6d38961b4f24f0cb2a3d94d2d8a11180efaf42d55d8c2e572e9a
2. 378747171b81dbc421db48b8a4c42cb2636597c35f7b7e2ef79f1acbf64f0b8b
3. 2f99b78806b3bc39842b3f9161569d77f168f6569bced904112f7c0aaa4fefff

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.