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

0e331f050f29548d8c289efd729bfcbaf775bade2950f2d50fa61ba14580e9da

Seed

5853b1af7fac8f3804a93549604ffd9eeec7213205ca4a1016496684fb6c90a5 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ce8f5b16e0041accef8107cdad819d04

Commitment

Batch 58,967, Merkle root 2f5e6f3f6277ab8a76a6cd4578265da3247a42bb1e7541995fb6ebd86060ffc2. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 80517b109bf9e5ccedee2ee620e4102bbcd7c7c23f355c3e600fb05ffe26e9a2
2. 862a71fcd26ea4d268fab3507946760ac5ec178ca8297668fd2e5189ed01475d

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.