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

01cf9512efae9a791e84371ddd42229e6170022fb58d43bcaf8f4ffd7a64ad93

Seed

10d52652e5b707e9d3b2e0c0ebfc8c81fee99f7893168c256e5327147ae7f10d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

80bb130429ffe7a8c8086b3ee2789111

Commitment

Batch 70,573, Merkle root 11f3e2ed7c88bf30f73a771e08a71c1a50e44e84819f4f72547c1ce1d81a8be4. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. f6a2fe2d9e68739201a11c041e2671c8cbd167609a6d1ef7fb852dfcf29d45fe
2. 028cbd88e5de72caf3d2e419eeb15f87ec46f3cc376668b4d7f7e92a07b52b37

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.