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

8c91c7c5d5d21302684f7896a04cf31762a105601c5ca2ab482d3aa2d34ac211

Seed

ec44fd8d81f4fed3df8b8c46e46bc161cd7ec3f86b3e5086f55b02eb1e27aa7a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ffe1d6918c60018623fa043cc2ad1115

Commitment

Batch 65,517, Merkle root f8bb22ed85a54c0ac033ef2b8e6b68874e6d74c01d768204904e938f397a18cf. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 0de67d7310d70d9046ba40979268af36d773af8bf71dc2f78679dc8a9cea0fde
2. 8a318f5c3be70cd328f538a346e99ee5d616ec4ce525b278f5d876bbd855c6c3
3. 283308da0ed49f8398cffd060abcfe348f9ae0502c32ac386ee10c384ecb6151

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.