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

f782cb13d1abb094b7b18b5846f85b3f1cf6784edaa7dae2adce7241cdb0c822

Seed

f18aaa4d20b0e02a6ce7d7cd11f3a43b8af0b98a1e1d49f142a737aa126b547d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

bb963a468eb43ad784d8d002f584b3e1

Commitment

Batch 59,082, Merkle root 8f697dd72070fb0a04ca20f836a56d29d64772fd9b2a4ff16fd8200bc873ca7d. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 1d6f713aa40d82a199afa965e978b8d3f287c4989fe8b5ee2fcd604db6dcc22f
2. f74bda35b3ee999b34614ec7f176c8831543c19f13a1388b401d7663c5fa8d8e

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.