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

35db3a6d65240e06cf3d5334619d97b1066016f88d8451c4b40741fa38ac15c4

Seed

fde3a519af330b9fba080bc182f6609c5450dcad0906aa5a64ee1aa849159f4a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b42977167c31872fe64d8cf538c6d68d

Commitment

Batch 55,128, Merkle root a6a9bebff1d7ba7b1d93fc1789a3977d56c42b71da9062c71cc02a0d79d5751f. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e4600cc94c3d2a7fbe3fa728cb7d57a13fde699be7408d89daa6dc03eb2ac522

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.