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

cd6a4e938f62e6620eee32debd88b90c2df0decda8a4b5a1214848d5c9fdd0ee

Seed

40cfd7bf2e73567af6b2dda815f324b427b188e56bb7fe4795fd4c17ce0b6c9e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f5d67316447010e7dd5588d1149f1e86

Commitment

Batch 61,186, Merkle root 9628a207c98a05bc4a9c1938d0b073c02ff05b982e7f5e4185f5e6125825e86e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 3bb480e9c3b4fb142576e1c43411b8172cfed0da93fb9f77e589c91bdf7de7f3
2. 281fe9ff216eb29464680054c75c81707d764a503a5c47ffd4d1495a41e2db65

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.