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

49edb8528d1144cf6e5feaa3ea920121bd1f8156883bb7b9aacc24f3e108b56f

Seed

38c853f3eb828e7ca0b04662f356b7ac80287d1b3782ef9707999cdb2be1cdd9 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1bbc600e1d6db2d7a0124425b4ea1f0c

Commitment

Batch 48,672, Merkle root 26a94198825df64c16a70e033e31c246ddfaa8265eea4a9ec98e31119ef6b56d. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. a03daf1557e97255ac46b5b7065e61ff633f73e079e2eb5398afce59861417e3
2. 5e8df83c73507df8c03dcad7713968f8cdd1c7e72275b3200262b9b6256c0b6f
3. 0b5807977cfb10bc11e8f3d90245faca96ba1d62a3122f3b6375355f5f53ce22

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.