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

189eedca4928ce7231ef1048533d26f7a7399a40194dabc0b75100805bf69a03

Seed

bcdce9ae98ab0287cdaff92d59ab849f8ddd7dcaf44f52d580970deb5660fdbe SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

e811198778b50fdb6bec4694b2cf0041

Commitment

Batch 54,674, Merkle root f430285ad417a6cca12ab04bcbdc49235a621b36087cdaca22565e885d9f796a. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. fedb5be8966828e03a226c629a186976061da6b7fd70ee3f74c66b2e06a01646
2. a64aa4609bd876210c11b36dff909034b179e0bf00cdcba1edb580d2fc9427f5

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.