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

e94d4809321edc89e9ed0b5d1ff46441409b64f630239e1ae94b3339012ab724

Seed

a6eac1f1ed81a5cadd0dcd1de75100c3f2659e7d621f5fe5c30b91b19eda6451 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

6d7e0331d71598db04e8880b4440a5dd

Commitment

Batch 63,139, Merkle root 2930da09d88d0d4093eb978e530295da1c5b453fa0f9a360bda5c5548fbb03f6. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 3828bf0a72dd6eb5637786a97b96ef35c07e28a9b33768834b765faa6475c789
2. c3c70372765b6f2557fa7f1876ab26f28d531918a3021f790ad50250eafce587

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.