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

6b0767096d703f5439c825d4e9da8bf1d2631f51f9c28b4622536fb2c9f552f8

Seed

031e28411cbe2f83550e633b4e4481db803d160c9b10d581334a7c6db63c1e47 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

af6c9dd627447292c0bc8a70004c3fe7

Commitment

Batch 70,691, Merkle root 577fde785519b12e34cf760af50add8d53f8c0b260331bb8be950c4bb0c03263. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. a498de3f3f8e7e7a8a58d323434e0eff088457b73d5cc329223aa5803df93da8
2. 1621feacc5e63d7f4cad6c8817a4214dc77596ac6a18ec15d3b0113877737092

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.