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

2b3ec035d9392acfe0c7f5468cc40560bd895a09a84d94b07ce252e8b3badbd6

Seed

8a13d74381c380a6a7e0fa62d51ea9277046aa04c5f490aa747e7c7c67adca21 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

bb0eba8e1c4ff79bee9d0552edb28def

Commitment

Batch 65,037, Merkle root 05a3ce3b422de900eebe298afaa26aa747057b5c0a435c0a313ae674622f9657. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c6a0f6ccf8f53c649c8522fcf8f5774ba19a3ddba5df780d2ce44e8b9e9b4422
2. 37eee180a5bc06134e637228a013d21a45c3da9d6ee8618d1790da026707fcfd
3. 10ee59cf690d07248ed57345d23f8ee3f083d51fad5bba3c5d6e797fcb2f0e16

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.