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

4df2d254000882d0baf5f44ae3ea0160a7cfd069da923ebfbb166dae90096ec9

Seed

244a8b993541428b3f876a2fe5cc80e86a41dc9b30184c6c12be48cff86127f3 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

3f9ea4392bc69d2ca87f6a80f6e544df

Commitment

Batch 61,527, Merkle root c98da3434046db16522cf1d973c0bb474e5cfd5b4e0f03d7acbce968c732cb12. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 86934c97b2fbb4aadb4736c4ecf6129685fdfb55e157f3a9014c01b63527a1c6
2. 858afed7b560c7c47a9d11a851052e4ffba9bd714116a091d57394c3d1560380
3. bdf96f0b6ddeba42f8c0e14f8a7f8cdfab28c0194d107057349be6e3c265d1e9

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.