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

96d5283eb270812f3d85b6e46f14630a73fe32d688fc4e272d4ee1c87b632e79

Seed

6967e4cb2dfb2c56eb1667bdf7aaff477261bce57c42ebd36158330187fdaffd SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fbdeb85920d88210d60ad2e9a4115fff

Commitment

Batch 68,667, Merkle root a6b86752d144b2515ea57fbb36bd3d329a9036569cc601dd897432d07a19e092. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 95d55ebfce29f360ea8db55a612c8b8d2ce4afb524c0ae06444a89d414eedec7
2. f2134f1fcd0cda33cfb30d29cb1c6250912a63db457649aebf4cdfebfd7acba6
3. 8f007f8abed4283b97a2630996bef436cfcfd6a220dfe72acf60fa60816ca897

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.