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

324269539857e04d2066c6055b8243a5b3acef36a8bb9643a64e1e0af8f640a4

Seed

e27e45c7172b5d47368aa54c825787a5b02dc8f0ed7d0492d6c23bc2d7733600 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

49cb914a9c29ac41368634915a6ae5ea

Commitment

Batch 50,317, Merkle root 185eb073def1a68347c4b090ac7274df362f26d6a2fe7116e3e7da3a6262eeda. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 20ff630a27c1d26468560e1bbc668228af5fd49e4e0155d9133839cdec55dc54
2. 3283ef1a39e1257912f345b671b214b113ee773cf70dcf5cf160fcfa38686acd
3. abc60f92f36a4435ca28187f421b6af7cf3e4bcec9cc56206fda5b2acbd36cd2

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.