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

2463fc6f4515b9b869cd945e98cb1dfdf0529e4d4437e226c4ea23d9cf629441

Seed

afcf98c81f39bf9a22a5073bcbf8148790c6480ea6f3569b6c60f50ef9fd4e8c SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

797a051ca63a44000f2fa30534251a84

Commitment

Batch 63,025, Merkle root 9f0a9601050f133be3685942a988c43793517749a552aa471d8c8c30c68ce10f. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. dee11838f2425e432bd6a6663bd0d71ba7ecc61b6e36f3d1cdc93976726e3a8a
2. d3db688395331567369191a850990180e6ee97d548b2c048a259b0a4e1022acb

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.