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

5ece2190afd2a135e57cd959214fd0ddf3661275c6482b20b8e147ea98c0d6a6

Seed

5a96901de71d66c60ccb49b63de9a42aed69ed90eef6ca6bbc5003599f035875 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

6e26400302f55853ec1edbdd19929117

Commitment

Batch 60,272, Merkle root 36068e40d5c04b115c0eacf204188515d45e36b1ba21ceea2e152cdbf12a8c90. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f28ef735e0862fe78319cf04aba727dc247e207227fc831d34ea656663bd30c2
2. 75e579f1f6b3c0a3169569f6a18c47656d08400b16152aabded110fa28cae503

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.