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

64ffa637c6b54dde9a2d76e052ad9013aaf81fe5429f8a856aba44358f96719f

Seed

8d5885c990a21e045a1a0db99c8da3f514fe7b2a0e9a9f229565b181f304fff6 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

7b3ba8a7087afae6d161d9c8209f663a

Commitment

Batch 59,337, Merkle root 1e3839fee2e9a642c61c54569a46481187ac0553c9a003e79a4ce8cf8b233fdb. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 780dbd178ea7e76e9a66642e312aa6f73874824c3b826ff312c3949d193f9259
2. a21ea7dc98863bd1e7ec9d760b9a185779095e4a0aafbed965b464ca670c402a

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.