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

3da3964427f724b57c1d6c437f98a6515f17248b174ad5f157d5db35b9479b97

Seed

0ef2f8f1459e792d5a14ad25d8da7209baad8688635fe1660b39bc33bba89419 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f0d6d8ab8037411e9a4e5472b55a2925

Commitment

Batch 49,928, Merkle root ddda8ee52d2051e354a3ad6a8d4e0db695e0387e7d624eb7d5bb4e2d40017813. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 66f8d9d9230e36346b4474866fb792ff8e2dcc8467660dd9e0d210e86768ebe6
2. acdf810d90aa73c08a06fe8413db948fad0579eda0ba9afedc9919239cbce382

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.