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

cd180887653312b58060972529fd3964965dfb93e101e65308899be634571f08

Seed

6cffcb1703498b551bed6aef3a733353ff51bce3ef225abf4d05a44fce8e81c7 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b15f714d4a284f282335ce95eb85c4b9

Commitment

Batch 47,631, Merkle root 8194f3983422c691f7fd83c8d5860e70c1c597d3e4077440dabae6baafca5f56. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. ae5b361b1f97299fa4cc35628061e0557ce5d4ecc43280a91948fab1002270be

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.