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

7c22c33a3f3e1ce5a4448a4b5cb10a3fb1a8e0b3f88c150e63d6a5fdff92e9e5

Seed

c744874dda05c9d6ab630e5a652e8c427bc9981ac40f4bb42bfbb73113c94255 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1fac39b81a7871f3657a9d44c4af3681

Commitment

Batch 61,763, Merkle root c68ac4f4965704885965d27d09a9d46debfbfb5d0546d54b74624cd47f7d9cb9. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. aeaebd52c5032d72a2ba13caa681b262d3e1e6f8d6c0c7b24101106561795b71
2. 923f956bc7b5935a2bf3d15c394f0c89cc59a0d35246ab5bd5a527bd213569cd
3. 79c98984f5ce3da2b7061ce30175a5241bfc8b2f6fdf3fb9ae7fb22b6bd195c6

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.