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

4d8b56488cd4240bdfad6fd55f6ca2b8c8bc6323664b273bc788cdbed4f06865

Seed

86c3c5f1c82ec4fe090c3d750cadd967cdc37423b7df4690f766ff3c35c3134e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

631ed93b7fdf8f452e5eaaf50dc30fa8

Commitment

Batch 72,442, Merkle root 131c20f8345f0d40951fa454c71fc7331368dccca6a4b82ec08ddd53f5d6b661. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 2ca2e036ce446d5cfb4e9aa05f10daf6baf475dfec4f03ba73b41096588b51b2
2. ec5cbfa2491cb55f3eac91a8b2fc1627b9be487bae8bb4315ecc62254fafcd25
3. 6a6db40d010f255d96fec9bc5b07eb43ba3607d7de366ca6aa1b4fa5d10578e5

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.