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

7a9391b7b4073ee1c3f733c7c2c18dabec6c82a7f1ad1fbeba2f0778318f3295

Seed

51caac8f82b3f3f42390fd07396d998415b0ad42968c60049e11107111414229 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b00a0587e18b60bf564dc213f8d4beab

Commitment

Batch 58,035, Merkle root eb27eb215558e7108d25b2078e77ea2147966a59a73588e4691cc9c3e1d37f84. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 67fcae13c60e30672aab4437c38d4d1ddfb529269afdfe8128438ba7cd7cbad7
2. e2a744ad46f1f831c638915680de9b619bd782f1f630d1d2481c9afaa1219d9e

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.