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

8fe29eb1503ed23e7e0167304ffa7603d5d462dd962ce19f7ca061244d60db93

Seed

7e9eb7201ca4ce74824ccffa165dffb67b8655409baaf43a2e4d54bb3f6d470b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

a7504970fc71047d39da924cf85d7a40

Commitment

Batch 69,787, Merkle root c87bdbda4dedd8f6e31db0772f7bdf182e06ca45407e15183723aab36ce10c85. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 58339e7db69649e27becee1b30bdc488ac785d8a1851526ee8df2ed1b2099f5d
2. addbda45cce239d648cbcccfc2e668d8875c2fdd7e8df257d38c7a26627e2068

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.