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

f168891a4944a6e0e42b7fa44694e1bf006ace625823c0bc0f5db97dc715acc6

Seed

f0ce0fc371fffbfa4a19f8de485ae110078e3d419bc69685d9b7a0c2fe89888a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5900f90a2f171dfa07f4f85ec9567e86

Commitment

Batch 52,400, Merkle root b1b69784f77115183d976666f9ea8dd6e2abe4b84b806f48bfa69e479181d099. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e29276d144c1c4a7a4f25d08ecda8f386a1b2203f37490f735ba7cc741f9583e
2. 686a3e4d77fb12f14b110ed381db0c6e9706858cb8bf070d8bca740b071152a0

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.