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

5c11745444be746c536cf5ecf97e56c75d6d491896890abfb3bddec2df49274c

Seed

2744a8d0220e81566e96891549e760edf17434f8cc7a968ba3a28b0ba0ce764b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

14579f1c3ded53a59d302d6ac6cecdfd

Commitment

Batch 58,156, Merkle root fc048ca90fc908a9b951e972d01182b0d4423d644c5f0886c66e1861b1b03c0e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 62ca298e43d0f3bf117b31efb4058059dbfbe6c2c51b0d3d3f6693d47519cc2a
2. 3ec50abe4e06960b3d5e7a3cadd858713be993061dd92620fdcb2ec557e01d7a
3. d9b4d3cf84b58723920c52f6b163b37ea6534dd09c71322888253a23ec92afc4

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.