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

9d887748b7b7458890a729348bd97f5b19e391079442cb1a3be1165a3266031f

Seed

b7537d1edb1a6304c30bbe0be1b4b6979820c66b4b7f5230dc7446e3267b87e4 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

3b23352bb49258a4758a1bb9029616fd

Commitment

Batch 67,903, Merkle root b70f38d188b617779c280e84c258928cf6ec068eafb305db6bfb50dc976f7190. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. a5a5a02ffb39df4062e0c779699fe30f57f1aea03a1421ba91e8bc6c05be7757
2. 5e5f274d85e9d92b6ada4bcbdaab490dafe1147704bae073dd323adec5cd3a29
3. 194304c329173de06cd6c45e6a0e2b863d65deb2f8f3b9814c71291f2372f5c4

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.