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

23d3abd80424143ff67de3b7787d54a983e90b41ad55fb0fb2de45ff168e3bbc

Seed

52cb2d3603b719eb1fb792557f303d0c379b6a39b067c4c7d1660846ec753001 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

e4b2304fddfca4fe3e8398929b3b0fc1

Commitment

Batch 53,499, Merkle root e7d994a5507afd55bcf3ccded6de13c13e199076c54d76691afb3b5b7c8add69. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 7518b2c081a1c160124910466051653c9a9aef73b4c142eb10492ad01fc43269

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.