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

6e5125480e855520f7947a68d6c80395f783cd4e38d3dea731c60b617dda03f1

Seed

3638b4d6053d87eec631801936828d1e5482c652355798a01cb2145b34af3f37 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

af8566b1a074c0292fa9f939c45dd194

Commitment

Batch 64,230, Merkle root e96581eedb8f997f89799292c9d4aff414edb4adfe088c909f0331673b416b1b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f2bf2d1feae44f2a55490c05125aad6773e7af247bca928adb75d19ee608faf4
2. 1d6a15837a411cb7cea11581abd73368fb47f5b13aeecbcbb57ee4171ae23fb4

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.