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

31d5b98ed38f6dc281a1204d75666f38b76946f6cac642351f9e3d9b1bde51d0

Seed

70c9ba39c7d21ac9a80a69322fdac7d5a17838ab7d3553e760b19b1296bbfc8a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

6aeb0a87e82eaf2fabeaf6452c3a22ff

Commitment

Batch 64,118, Merkle root 5c575463aaf90fac03a2a1d6210b283ed4fde84f13d8c30c08ad46574a123c89. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 4a8e6f87ab9fc72c7e5cf6644f4cab350c3b01520d4dec5ba2e31e111c76cb1d
2. d5dd3bf5b1e608ef349eb8987981d69f0eeb1182b5133dd7fc7fc290de442955

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.