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

8aa5d57e1db33ed864d1aeef55a6d30ac6fb3aa691fce4795c6e351da6463cdf

Seed

032b9bbd32e8ba5f4f36f468b39df7c3dd6e86f1e863f3e5ac288bec7edc412e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

28eb68448c0c5d8f8f66108c44dfa35f

Commitment

Batch 67,332, Merkle root 93105673d5c647ecfde8d0c6c63733f1bf527693bcbf9b216d6795617e63af82. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 36062b3ca454ff2edbf2595ec19486072251e18715aaa283ba04c96b15207a26
2. 3ac95c181aafa457d1735b7fa26237b8266416307990c66521ccba043ba43f43
3. 3584bf8baaa4f8bd07f9851c64eb40514848d0fc7b72625b245af7a45ac6dc26

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.