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

68512960a21920abcf9a15e637f7f3caef7a8c41f63047b5e05ec630850eaaee

Seed

30c686d74456f0b51ca8c576ea22bb84c2c4f6b046426a7c7e5f7c7217b0adca SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1dfa22a42a4f49e60eb0e6383f79bf10

Commitment

Batch 60,060, Merkle root 4e1b0535d380e5b8ccd46ccf768f081a1e515d15276ab45a42dd940ff49a3d6c. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 900ac0820b4c6519c485a9e308165a0f149e698872c7acc0d09087e130937ef5
2. 4cf5d208df6864afb11f8a8baddff51aab6b716b3554edda3d938454249d2da5
3. 6abd23a7bef8a5725b31a1a1a1fdd4524d886e5cc5dff82410148dcd7fc56b76

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.