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

3ebd46eb8d03f04082db272ba1a350344d7c6759e623d6ab712f90b9d4ddb135

Seed

8835f9a6dafe30082c226a84370f29db981f4f50a5ff656df963d749309a5dc7 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

76324e6e73a23d22c5ea230967d7bf2f

Commitment

Batch 61,959, Merkle root 90f5a3330acfc4afbf610aa1f13b713b6a90dd7a7b2111853539013c6a5c7845. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 3ba79a0fbc5dade6a8eade0edd14e4354ebeb3f5cb71eebc32f7f2c3ecf58bd8
2. 46ccb92cf65a9a4c1b9eeb36b878fa5c632c802057693412e7eb7d301e3d1a07
3. 144f35cb88ce270989d22dafb317a17d99c0e39dff45319e823c84a723bc8548

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.