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

60e0c3c926d0577edb15dcc69fb07f77ab7ccc935ef122d81eeec12af48020bd

Seed

ec9527518d18ef337162f552f9173f7fb94e1c760340ce8509288395f7a0ddad SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

aeb3373c2f37aa141bbdb9a14d8afa90

Commitment

Batch 58,617, Merkle root 6b252c85e86bb80ffbfdf9f0ce25e130762d8a24885c618482cfa0fef88a1fac. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 148c61c86229b65d5aaf87b722f728f50417469dd7cbc67c398070ef06a037be
2. b70803ed3aacf626bc2a34f6a61de6f286f92e8ad6250836ad90b9537ecb7991
3. 497a97b44f1ab5066de70b9c0dce3c31153cce81d4be9356450b8d77c1b99778

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.