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

1e1530c03e9d94157c8ebdf3c15a369e0410e0fa0764cd4c8f52f6e6495c4823

Seed

ea0e58386a5789570076687c00f7a296e2361c74d91794244721bf253d0e9f64 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2e7b8854f7329c402c8f2828951d8f91

Commitment

Batch 67,216, Merkle root ea95bc6521873fc2eda6bf6d6d898bbd0e754d1b082706b0c2184184334a828a. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. db7e1594185a581f6349bedb8adad0c764e52326a1fef267a6c60ea6cfe18154
2. a17ae0e137083a21fa2cc383f085ad81a1704665f7b1870919f46aef86567b65

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.