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

c94cea584f1212e310543817de22aa7a41304007e1eb630006f03ccc2fa5ce66

Seed

99237b62f7134594c43b796d8ebc7c594b947bebb035bfe06726543077f854cf SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

823e93d7e5c1a729971c9e4085b64a83

Commitment

Batch 59,417, Merkle root c210e492d816e0357407152f86a982c50d1c485b48c26cace2d185ed5677bf87. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 4a348f3b38b96fb21c9d0c8bdef8dc875c4ff35319d2d5bfc95262460608f6bc
2. cda639ca8cc125ad1a551e602e1bdc99ed82fdaaffd810dc5ac250594b9fb8fb
3. 2f6ace9277edd7274f6b10f82c2e7f4242825c235f787890750be4763b9503cb

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.