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

00f9422507175fd078772a577cb7cd4c28568ce6d0965bae147bf97e83b1302d

Seed

5f539dd44774aaea8e61861b3ef5838b8b054d79148edcf565281a986a3d7288 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

56541b8441a5c436087947ce5ee2234c

Commitment

Batch 71,556, Merkle root c05b14221782dc5e5d0d92197e642edb360381e3ffe62e89d848130b0dbe6c33. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 1b31d52adb776acbd0aea69ccc6134edf31cdfe889081fa96a407a08325b1bda
2. 72adfa5f9aadd75472142cf233d003bf0b5ffa9757d8e3f3c000cca22f644058

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.