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

b9e102a8562c6dbb408ff3d545ac51c50ec9684fe10c975edd65bb948369cc99

Seed

9e98cbd2f1f01aaed09c8f9170cc59ba92fbd2bac316574078d4dde19de95c8b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5aba951ead65d3ccf6ccdc9e981d50cf

Commitment

Batch 67,883, Merkle root 17ccdd0a32e3c9dd7657d515f9ae8d4069c72d97d0bd87eeae02eb6bdbc3188a. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 3c483ae9b3ffed934206a19893528ee18a6587c3140d9dc038801000996209a2
2. 48d7323942a3fe48cdd0575363f19d09bdb7e156e4a2ba0d321395fd0ee38110
3. 7b7124249d238135c88049f1c06dcbe76a334a6aedf8d0a3d03a1277c2dc9141

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.