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

3473b36992e347c266dda55563630a01ab8c90290733c57e223aec3b3a7e6f93

Seed

c52fa009c3eeeb0ad918f121f8150d737bbcc04daecf6e29736fdc48762ee25f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fb64b3305b1f06290cf921fec0640be9

Commitment

Batch 61,727, Merkle root 83e26cc43def171b8e151660a30b9d274c39a4fe09b025b0540316e5043132f6. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 5168fcd0160b2651c1306a2baddde3897815021a57aeba36a8b865a56a689034
2. 81441c0500f399ae1e2271818461e70e07d0667185f1f6a84f15a98bc834e897

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.