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

512f25da5e9db5fb994e00e60fa143b9bc5c26fbfe39c9375af256143b8d9719

Seed

74627c72b96224c5a2e1b0cbb842b273f6d6a0c9ccc17d5cb99f1d72c10ae867 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ed14329f4e0594feb9dafdb539344a32

Commitment

Batch 54,282, Merkle root b6b7ae78c48f28f9d2f2221f54274f7ab7bc7581b4076e0abf9d0297a9e8ff65. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 52c7b16a7baf3d8f156c75538f08212faee87ac5993e2d8fde331085dbd7114d
2. 0081c3854eddb1f537af1476d69cfe1589e3babc86bb41674eddde4c0bc76eea
3. 327ce97c480a285d78b88cc14c1b5aaf9cec7f10b0fa7e22844cdd4fd8b36d52

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.