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

da346f411a9db7b452824d44db1bd7a43a3846ae43483f2db9380f5e7c4bc4d2

Seed

1cb5f00ca48c532d4307746a28e7561abdde4a9cc5a88d10861be862449f4427 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

08e823658116962cdbcb4dcf726dd441

Commitment

Batch 67,791, Merkle root 04a0c9b7f653a6a3f5e6e367a7d7bb5cb54758ca5092a299e46493a5a0c68bb4. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 85766ec38a5fa455c46eb631996a4be6fce847beba18d56d28388081424d14e4
2. 84e7e8423461664c4ab645d6e4af043f64f2fb90ab3e8a242ba566db4a9f4d5f

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.