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

83629826d0a58ef0526ce2dc617232f258338616dbec569c47a3bc6d02ba50d7

Seed

ffb983246bb266ec2c442982c3113b7885ec25d5a492c655c4951b5b1be0e535 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f0fd1848f6ad02b35a3daddfd2a54693

Commitment

Batch 57,112, Merkle root 9e2024c9c7007335e72657d552e51dd4a74138ea0504fb7d2131511424615589. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 580bf3ecc6c45d75861470cd3a74bb6f0e047483d7093156a513ede6528c36c6
2. 7a935acaf47654c7c93d967ad82bd746a22f94019198a1523280de1b57ad9a21
3. 1b2481853d797b3892b29f457a66470094d2638696a7235ec58231e8b1c19924
4. 8983cae76641697481d2f6a07ff1c381e625ee8d18da86036d20dcb26e6a05b3

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.