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

e64c48b7ff0a208f50bfdaac922226385786c98cd34dc73c0835d74f98d0553e

Seed

f0531114e50707bd853a7561b590a487797c5c57bea5f14b7f8c3b118d26b0ae SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1210b8bce427464aeb6579ceacc023b7

Commitment

Batch 68,471, Merkle root 7dc27c4c12fd16f7bca4706ebab1e808cea755cd373abf956096157983250415. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. f2ad6bfb4118d9686a116df0efeb3132d06f5cedce0e1c0fa91e6250fb994651
2. 28182c0d244c307b38cbe22c5bbae97fa1f298df6ef871082aae4af9cf4c722b
3. 2cc15ac0c81f1546497b9156648a8fb1ba5a3d00976e935b04363d399b7ac91e

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.