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

1c98fecc5b8ed1ed5b65b28a51bf1d9394a272be58022d24c04de580ce827d4b

Seed

7119e34f8df713acec993489d83eff23074e5966fd228b05345718fb3eca3114 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4034d5c1c437d3f408e15dd9fd33f286

Commitment

Batch 63,530, Merkle root 3a282ce5c8ba687a7380b6354036c56b5b1f5e13e7d99617be0eb368cc39c74b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f434b65def13fb5c8fdccf778ea201d1a0d3264bdbe09cabd0ac6185e3d6999b
2. b5b8b6ca8f16cb1103a4bee3c8438ee0e9aa00b5f713a88c99fcda85625f863f
3. 166a5743835e503599f50a0d7325e9a6828c08f3f0c786177b791903cb244e20

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.