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

9e152b616defe7c3552dc45413b697302c76db6fc8355d1dda4a1ddd57c5630d

Seed

1629d5c9978edcc3052aa3f9a0be40cfa17f652c43b3b587a7f4e7aac0877d49 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

554f7a2c15277c6f21793a659abde4c0

Commitment

Batch 66,639, Merkle root 223c2370b21ae22b905450876dae8c12a8fd2f5a207be0e52f613c5ae64d9a4f. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. ea2e4a8c9f76462744968dd13894ec99bb536693554ad2c8bd8868d2526296e1
2. d3904934e0fee203d4a3a7e323dd4f28e0da0fcd0928cc70755b0cfc14df5959
3. a8651eaf6908fd0e98c49c3a22d46bd9c941b298b9dfc8018e4be13408e19381

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.