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

39af4c0127f7b3dffb42d1bc2844601c7386214b2d071debb217f9c5b3471158

Seed

1f50a36082488d93974954dfc5b09d9d712e69a9c4696186b871544edfa5ae73 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

52ccb4ac475ae943472f4dd6c00e095d

Commitment

Batch 52,371, Merkle root 05aa5e6717cec99cd91b3b7b32907fe0b10a0242e6b3ed412459ffdb5887d291. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. a5ab3138bce9b225110f30ae3c92ab0d81081064b327ff984f2bc4dbc5d6642d
2. c76984966b118f40a51c6218f601f1b95b7e5b366106fa9d214f069340e6d30a
3. 7d6da197c40daf8522267741d4261ac07203e17179d69c4212754af2998eeb6a

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.