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

c177bbc4ecebd98a5072742dece70b8d4f5a491174b2b1503bf6403ffbff2af3

Seed

ec0a76c881a3aab7fce262ec74f108e7f1d0ec114100257a81c7a659082785c3 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

0901abd330ec67ca77114f1f556baa8f

Commitment

Batch 67,997, Merkle root dfa6bc8ed4797e65617de7d1ded721a8d53b1eea963422808d958c21e49a2183. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. b13fd7281336c10980756af5b57854b71d7d7f4ca52bd6a12edd3cf2c4cfd2ec
2. 508ed1017c3e8ea713920fbb77a8f66ec3df352f5d46281cb16a840d1785ac45

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.