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

1acc6fe73f40cc05b497a111d18326164a95247dd1ddd59c57148a2d5edce7ea

Seed

7e51b5fe7ddb24978f83059a9efb6d387147c53f8429ceb6d296e9862ae9db46 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f2a0f18f60a15c1ed6264612573c8ab0

Commitment

Batch 57,929, Merkle root f4a236b6d5b587649882e8cf0837836bfad4e45f76ce7211a7435738d2f85d8a. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e60086723d3481d2280eb46cfbf8f1002a2cf8fbb5ab150b62cd105d1ab66c4e
2. 8ae4658f511db9d3ada024fb7a76b19a1fda7ec16aecfb6d078f7cd0bcb33842
3. 3d6a92ab0c16910fe30c87f2e7e12c6f6abbd95945649c3d332ac26eb286ccd7

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.