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

5ff7dfc5e367583a0837e50575ead1e2e0b6bad28abafbe94dae9c5cc7565194

Seed

0750b13d0729aef8a727f2129ccd39dfc83b639f2413ae9da0d8390910da2d04 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

de71395b233cab8650f02433b2c890ec

Commitment

Batch 57,226, Merkle root f2e3368c44fe437b42625c8b2b5acd51bedb4e258ae81f257c1ade2ac835a8d7. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e12e349c6f54bb6b77a90fcfadf10e802ef5921a502155ce52e267b97b8b1968
2. 4dae4885cb267bfd27eafb297edf6742c7eff9ed74a34cae06be04e7bcb9e9b3
3. 4d5ab0e5b1bd465055bb08a6e76f0d0adb863c8343653943e72827cefc39512b

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.