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

171baee304784d7225264637cb82726c9a7542edf97a4d2a463b75c87f8ae18e

Seed

ad5614f6fc32fc8a56859f94eee128e185dc3eaf945f562d093e16777803d8c8 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

0ea521a7ad609e5f1b5ff332069b2ab2

Commitment

Batch 70,731, Merkle root 93127dc54bd523350e9bae2c15ede48c9534b272eeb8e53a85f69d6b3d916fa7. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. d55164130b1c232af85d7f9899e7d2f87379c1a94521f859e9e5a928db518218
2. 07ff37ae3da8ee71420e9b25dabc155b43deac1f14d4d6aeea73a7af6919167c
3. c65d2dd1d2c30832e874b48473f85b1fd40a125e8124bdf46cc478597ea11b80

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.