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

03691acbbb6297f54014ca2b2b0bd43ca46f589994695e7b2992b740c0c62c78

Seed

b51c684332bb8ed0f94a8cdbe646041787433c4267eae78f045decf73293a5c4 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

466286767317e86c1e549ef7e5c621f5

Commitment

Batch 63,253, Merkle root f38833407547cb1c55a2483c65347b3c1c221e01a76952ecdc5d6048ccb099ee. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c18fbd731e232fa57223d7dd3fc50372ecffaa98a69658503f0783c444f89d7f
2. d176e67f597d79071ba39b5d3a74b336ce465c39aad03c4bf604163980b6f3f8

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.