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

4535c8a2bdfda0bca80ea3860cb57ca65e2dac7fc9364ab2034b17b5e4ccf1c8

Seed

171adefa4330e60843e7ce8f4dde90c6b38b30e4070e6658d62926fed89773bd SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

285393e3367012e703ba07b3f8883900

Commitment

Batch 59,655, Merkle root 92711f95188d2935199d603fc648cf48ad6366dee07d5edebcb9aba2ca7836b4. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 1daa7a56a82a850a74fbae4618adc24f830a2f800eb8f62707e6945bdcd8c81f
2. db8d08303d9735aa1ed0875185bf811d23e40389b4666b81f7ddd9837785ed22

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.