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

d500103231ef1428ccd3dd410dd92b46d1977bab845b8e381a26d36cf26702a0

Seed

8bc1fba78c7f69c96ce81ca4493bca302e97aa05de2eb7e403c86254abd8f018 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

29d05bb2c25996888c5a4ba10ffa634c

Commitment

Batch 68,802, Merkle root 16cf79592f925597c099e537cbd8c9ce1a0b9fbb35a36d32c672cad387e155b2. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. f720983e26fa74028c2d1a60af898dc87f50aee3dcfab660b79cb3f5240b06fc
2. 74101c7b6a56ae5f616727a6b1b200353cc2fe69fdce9dcfa321f6dfaf625819

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.