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

30a16f79504482ed7a8e6effe7c9f9da101b39e5b59f6aeb74a662d4e5a1e81b

Seed

f02e4f9a529d629bdceaeba86c280f94d3004ecd1b20a06723c76d9d07d42e88 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ca1d541f9118e7b47b9e95b777f3ced0

Commitment

Batch 68,099, Merkle root 35c6a5d995a2511e2a4f5b723b7abad617fe17992f812d5c6bdc28accd7d2c14. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. c6f53fe919f59267953647fe93338fcdd83792a3c05b0e7c7a9f5be14fc56f77
2. c14b72f4c6a2d9b0ab2a4438e07170d0d6fd33e24a37fc7fb9939e2fd3b36032

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.