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

22f1f12d994155a81655e68443f27cee10ced7154cdb21bbb22a5564695d862b

Seed

92ac370aa7aaea926fd5ceac83f233ac50b92deb27545710f39508456fd32dd8 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

944ba3dcf1b5ecc36c5cd9899f9e2476

Commitment

Batch 48,048, Merkle root ff4ad573e0cda4b725145bd8b402d99a93a038b18bf06cda0544ba8faea257aa. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. af33ec7471b54a5d351fc96d2cbc59a1597b6cec51e1a9a41657d8c433f32aa2
2. ea11d6ec02fc3feb5b8f25251c6b6d1554209ac4df8161c67db5122cd1c6095b

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.