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

f526f137167d6bf708bdf143e2239525f84b9b99ff176d27eadfd795a77a3fa2

Seed

44db5646151f9630c91952a6b16975aa8ac98a055ced670a9bdae34e39e8bba4 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f8bb9d206a0367ce0d5ee58fb52d218b

Commitment

Batch 51,129, Merkle root fc907f1114862a4274a78cc7ebc4472b1b04f3652d239002b4ccdb0d156ae2d8. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 9f733a750d181fe87e211b1e30c6f440d68c3ace3311c475a65572d847b1ec3f
2. 2bded6620f0169f0875969485eadb0cd4f7682d500e925fd271eb581d819bcc5

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.