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

917996730ac7ae51fb3e3b0eeb7d9aeb47a859f677db8711fb6aa497c5252994

Seed

f71c7537d378d503e656d6bc280e399e36398d587ef7c1a7b559744d3a846c84 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ec8b9ba2847cae852ae2ca11af3b7039

Commitment

Batch 62,459, Merkle root b26b3a8827283e9c0f19e8bc930e7a82d219121a47f4886f56349b0d9d92ecd4. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 062d7774f326322e6d6352e205b7ddcb04e6978a6a8c75e26d7c9a5342ef939a
2. be85552adff05e5bb34ca9899ad2fa0f6052bf33b62e6e3fd679f14aad531d81
3. 60b151d429abcf0120bea4228b2abca72d605e40bd66a10c9adbcaca2b347760

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.