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

a705049a2e0be5b1c634129056d8bcab2323e0b006771674f0e95caa12eecfd9

Seed

d1d7e2e5a361d56da7d678efa3784cc1334bddcacf1239d52725a86a0d79aa35 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

7bc15e2c1d9873542566d54cf539d107

Commitment

Batch 50,557, Merkle root 0aef7a51a949e5e257e8ac63d5a675075c386982ab449f861507d5373245080b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 1d784b4c4c7041d3d155963767345c5dbe35c8325d52e79efa6af13e51cec9ff

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.