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

7ce23bd8a581b9656c1985c7e925305526be353c6e816f5deeb6a7589f5e2a8c

Seed

cb5e9fb88be29dad9a6c944b7c957f46078c74ffa92e21dd2ce0b1ea96f70085 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

821b1490bb4b3807673d5d0e5e2599d3

Commitment

Batch 73,509, Merkle root bf8e28b0281456c4ff9938b7ec7c5f98234c7431d1050ab019b98ab98da40e36. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. ce78cf6dfbaf0505018e96323f26dc566cf21bb4a03b5c07012024fedc10433f
2. e4736808f27f6042d86d37deff62e1a256b8161abe6fd843f8c21cd3b579bb3e
3. 44e60192f809475cafaaa2078d3b5bbaef270f3010925a089d54153d358cd9dd

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.