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

0e019d4c6003118d48473096c902f0bb0a2c3832adf747a1d69dda82af71b115

Seed

d8e902bbfdab65c2f132fc50d1ac1ea322ecb091d8c0b2ca9389a41f4b57b429 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

587c4d7418f468b5c5d3b354779e76a7

Commitment

Batch 57,464, Merkle root edba172cd5511963c916ff4f290ad26492ad6f4b4abc79083778a3ab5d6f6fb6. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 23a6f8dd456acc4acf423678385840362c14fc7c5fdf14975d70bba9d2c8b187
2. 30e97c9b2d58d261f85693497fd36bcfe0ef9c4a194471ee42bee72824aaef55
3. 48ca8c4d889093b2c0fd6e7c6cc57a29a6bba542f76bb7b8ab50edf9af994150

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.