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

7425e1045200e1dccd00238283739c0bc6597ab4bf93113943de38ccfc42ee24

Seed

ad23b96d486fa881b68b39dc7bc654627ca937068e985c6578ea001f7c7085f1 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

3802d32c61843acd1d0bc98a417c076b

Commitment

Batch 66,406, Merkle root 1a67d25673d2fe1c1ccd12ef0f7a7184acc2de144c820b5c1212719df614a3f6. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 8c9b8ebef69cf1badba9d61262efb5348fd0e91334daa4251ed45c99f89ec505
2. ad3467e870575ef1cd761972a35c46514af8aa458207056129615ce635dd33d6
3. 006d36dbeec3ebd578995b2b4c1c90ffec9ba90456a67831974a824426234eb7

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.