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

53f2615c9ba3c05568b91bb28c74fd852d45a6a35c0ad26a038066cab75efe7b

Seed

18ef09b65dc856c29677852194ebd5712bbf8a9f70c1cfd5d6d265dffc63676a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

7bd68dfa662c55277ddc3db1f9fd952c

Commitment

Batch 59,129, Merkle root baf40e4064618be60acd094c01faf717e85c55a7c8a8aa5b0f629f47a1948843. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. d5765ee8089886c9a2d9b70381a5b431cb55a7bdbd017107189aeb2f3ab0a00f
2. 2aa257cb2d284719ee98b57015cb20c911d89d78724df1be21aaf272e54fbb25

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.