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

b52ab11af1367357347da191536faae36f477cd78df61a66c9be073cf3c32d0c

Seed

aa96f713d8aeba5a0a60ecff80a14ed48b9cf70a4bf1a028f7b56d257fdbd887 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

13beb7cd8424dc826f2e04683df77cf5

Commitment

Batch 69,106, Merkle root 8dd872ed1b7146e364fec6f2c17aac5c0e05939bed771838a6ab22eeb2d569d4. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 8cb5fbfa55a7431c0be4189df718411c4dd60e394f4247fed4c405f106a3175c
2. 29d66cb36b623ef25ab465ce0dab760fdbf33b9cdaf4271fe71cd9e8fd3439a8
3. 9dd73a04d32f093ee98bb6b75a08f48de9ea24829e505ad64a69ac0197df4c99

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.