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

6984afb44e95a464a79901533fbdb18a30c7c15079c12cc832a5c55e742a3f49

Seed

14ca8392a5133e5b069490b5699ef51b36f26673e19f2cc3272edbd81c275604 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

82792b0c18e828c1d08d88aff7681a71

Commitment

Batch 61,040, Merkle root 23bf4470b656422e42a7f9eea581ea0cc88f068163b252916a01370f2734f844. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. ad582c155dbfc5d1ad4a627cb3b4238c48cf8302ba4c525091edc4a6acbdcefe
2. 5873b12c97b1c653f1b8bd58673aae7ca6f489e21f51cc6103603b1f70da4fba
3. e7b1f281e466109fa3bd326c3a044a2539c3b6ad912c24dcebb83f761a6c27f3

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.