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

ecd67711a0ca70db920640a967497e05a9e13b31738edf009b483cd12f5bab2a

Seed

6853849bcb3ecdc1f9ab79323ecbe2620f5d2597579f4eeae6ef2326b0f8369e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

78dc31d780a7eeb423bac88265abb888

Commitment

Batch 60,039, Merkle root bf0c9f367ccea759129d5446a54ec2f74f4383f4b5f52c3e52b1c5aefcca1fee. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. bd2d39f2089f0e5e1f2f5d80aaf4de9e34e2bb8c695c8b2f4770778a1851aacb
2. 3cbb7ff85f088c09caa9b35d862231e28852fb7ee9c2d40f0167764ca5caf3e9

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.