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

39f9dfdb356254226270f37f61da23b17b643e4720d2df8d41c4220d6819e1a7

Seed

588aed92451ba26fa3974f9a50a2ce8af3677c95ac1caac72153c716271d6a9c SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

9c7d75f67e9f6b54106330a23f608701

Commitment

Batch 56,526, Merkle root e641509b80862c4afd37f6f0d9705db364969283f778cfd6a46ce232f6754e81. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 61fbcb2bca6a263cc0c95bba6dcb5c1e0672895cc4a9782a4ba846ed3ba52862
2. 59ac27aedc35b7e03ddea5189bc91906d0ae5232315f685f89c56c8d000f01f2
3. b4bf58ab502e34140840d5d2732d8cd5949f77bf9e2977f851cd413b5905ba07

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.