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

4f86368316f956ecc011f377ca2f60f3d195a2fe2911dba3442f6b92a77492c0

Seed

84870b22a3dc6d822359c69e4730ed9d0b64a965773625801c3498683c1c8ffb SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

8af6a102ba9b40acfda1b40231b234cb

Commitment

Batch 69,511, Merkle root b09e488960c082a073f7deab253f8f137b1b8f2f57bf4e961a13ce7ee31a1db5. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. d7e72c063a49634d647f3d246cccbd8d3da6afe8151c17969d4c02e8e281524c
2. 8c84f0e6de568f18b2a390d860e5f16f9c4b7d678f4bb2fc903da67c5c6ecfa6
3. 93e1d99e25e680c2aae53cd7562915f02f5903f5d3e0892abbea2c45eee215e0

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.