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

3df5363a3c29b27ca09845283f88caa451beb2285d9492c6c0d4e59c61102a45

Seed

245e538d4db052767139076524d54a2d1d0744e88b7e1580dd065cd88b628721 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

29d52fec1f9758812e88e43a6e5eb703

Commitment

Batch 69,028, Merkle root 63e1856077c18246193c54fc51140be05574bb7a3b534c5410f349dcb1612038. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 6415025b3f0ee37a2ea310d1664d01c932c0ba21a35d0c5c8fada1600ebda5ba
2. 23d0cba8baf308b7977cee2c57c3d54f6523186dd0486f5e8ad7c46178547202

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.