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

125891485335a72e3f502a63113dd90f25611802f8041cdeb357fd21d1e40c5e

Seed

9c0c3f133f7b891f3829474f22d34b786b76d912d5119e14e5811f968d1cabe8 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

c5ca9f10185c4c7666dd0a5cb4c4a6ac

Commitment

Batch 64,785, Merkle root c1d798fb352963017deb8f2016d31b0825622385f7503cb70ed980445f6ff7a2. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 7db8018d071772407f67ce6c592ab93db2c790b0b13928126f7198d644d121af
2. bd5d91deee11297f5c960e2b7b54544b0774a9f58d7e59821de831584c2266cb
3. 83375a9cbd3f2143089bcb50895186e43010c9aefc694f454a80f4ec246fce6d

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.