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

966f7afb768bebde3cc4ea3db54a590275117a7e98459559345520de2e5f253a

Seed

637bd539b253e74a008970adf5eadc73a559e0d79a6e0a1c6ca7dd84b0edde3a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f6b5d1637525ece37e5b9858681bb9dd

Commitment

Batch 58,741, Merkle root 562da5a04997c15d0cd2d6ff3a1b67c1f2c809aeb532115bb94f05cfe9b021e7. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 06e9f22772d8a8b3d7dce0a6d6f338b28382680cce22897f09000e98c8fd75e9
2. 110e86df6ce5723087978d27c6dddda6070a82f5ec42c238579ed184a27ac189

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.