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

b345ee80ebaa12c2b2cbd1f1c858bd711a0452cedda51124c4bc76a852c11ace

Seed

9d1602bbcfd3e4cb0d2520d3e5814a1312df803a633667f5ef2e64bba190bf3f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2740e885a759876e5f36dc466d999528

Commitment

Batch 66,098, Merkle root 5fc799501146e7369410b4ff507bf40715032c06510d81614edac7355e9d8a18. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. c8d4fe684aa8267ea95f5261b118971c34101d74e823b1e840c99982ed23b20d
2. 4dbef2bd85b367932c9292fe1dba67d3dc7f97497b34099e42d031c32c365cf7
3. c14d232c25ecf9b92fecdddba47c88c188a0ed7061b6dc91f3779cefc4deedb8

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.