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

6586a2c09b929791784fba7bb48fbf4a06b6cca502e78580fd70bc1fe69cf998

Seed

ad166866ec8e53231203494c0e331a9499fb1c4ca1c6133de25b91a72c20a659 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

37062e4750cc10f56ba632812f7fb0da

Commitment

Batch 65,898, Merkle root ae436129a6271d00daf0ae46928398d95b457f1a5f35cb0fe7011ad74df8dbe6. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 3d8499a3a4aaab95e36d10b912e70893c21f8454285d1544d8426f7c4cee8848
2. 065a84d4b7bf681f7f1a34de5b73c5f2e0782d876984ba46b670fc62db6e10b5
3. 607052272dae30728d4fc4bb78afd3818409ba5df8867a2179c920d6c8624f7d

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.