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

941776144a3bc02fa6810dad781c8a7b73901935b9c17df0c0eb8a9562405168

Seed

ca3b6c5568713fb2001f43cb3e78cee689eaf4cea293772d5edc9a197e6acb77 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

bca03a3dd2151a6e4b47f7126aa8a89b

Commitment

Batch 47,982, Merkle root e6f7b06424d5c0fe1655be30ae5c8439caca78abdac05d7bdb3f89ca1224390e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 8118a9c200761d346d2fa5c363068f1e320009e295afd96b4650ffa224e77466
2. 50dd41f2f118dcde209d2312fdaf5ff42d06c0bcb6e73bbdad5e6207186384f7

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.