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

4f4cacb3b628dfb3684f10edc3a97ab24c9184ff7d195e4f63c162301bec123c

Seed

285762f1d2b876d193d684e06e4c68e2a16d6f09da81feb9f1681a17929bbb73 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

178b32736541252f120fd5b255f39ea5

Commitment

Batch 52,285, Merkle root cedbd74b4c6d64abd62b3c9b6c22419a7400a9a45d959e12c07e0da70f766941. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 71c760fee94a4abfafdb7086494c70eace36f3a3257d56d5a1d243e74a78cead
2. c086cfae69bb73ab193a0d2895fdb4c6d77f97625cdb0c634656e5bd9ca3becb

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.