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

9c8a7376dd4b3ad6793522c18bf8fc29cc981fda632223e1b8818ff0fdd109dc

Seed

90ed9e6536558a827dde9258ab71651e1e78954ff7c7a0a373ba2d750df59360 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

73ede6b1311c0d7a590640df64e9b0eb

Commitment

Batch 50,388, Merkle root 78f95f175df7b157f2045305ec41edc4fa0b4ac29b51d65377d53afa26e48813. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 9ec2ae213c4630bbebcc2d72b2f66d34a7e002cd4d23fc1e3c8c1371d7ae4be0
2. 6d085007e4aec4cc1f87d632811dba5e57454e754a1563684505a710a5e2876f
3. c6aad71254c42564f0041ddfb6d32eb4f78cd3bad5765d63d662ff0a61a7fa29

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.