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

069c9f86970d6025167c14682460b97cedd28fe8b5015768154d6807afe950d3

Seed

33971cc19fd48b1e55e04ed9896256df7a0f8f735c4c989c27b239930bada28b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

980cc1a3b1d6a1c00bd2483c644d2f9c

Commitment

Batch 58,296, Merkle root d047a13626c7e157d80c5d686d4a46e4057fd2943a49a050729b784f20fac725. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e34a33dcaae4c7c3040e21b15d6f12de8d7852d058f59294edfbfe9656705485
2. 7963d893d614431ba7d40c5174ee0c90cfaa6d506e7274df2511511465c9939d

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.