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

27cbf2b6e32485c5b9f264500c9b0aa890ebec72aa639bb428d08b37b84aa864

Seed

a016f7d8080c6a25520eb08d72afc1932c7c61446fbb45921cea3bf4aaf3e78f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

3816fec958d02df45a3a2989e131c54a

Commitment

Batch 60,797, Merkle root b2c8d96bc850a5d4fdf22e8db95f26b2aac8fe4e2f39055f50ae4bab032c536a. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 8d0578f0316868512c2d38c92ee71578ac59aad29976f3bd85bfa3251d45d596
2. 9a0b04c86851db0c0bed5af43fdfd72f8288f0d87751732abaac9a48836038ee

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.