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

5447c5b6960e54760f22aec8884e73e1b2394bf951259c1cf45c68c406eebbd0

Seed

3aef9724b0495247223eb81770abbc4880dcd23a85c35d6a478933cd06ace596 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

048bf4a6171e7593c9bd28fa9a99243c

Commitment

Batch 71,365, Merkle root aeaf1ff946489937c53f72b261c582825a563035a16e92bc58a428fc07bd6ac9. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. da43cd9ced1dbe6b44fff61f3f481b4c0159e6520d805d8ab5f1abdacffa579b
2. 3c07cece6f02c6e3524e02558e372f8167fff311a9ad924a5e615a86785f32a8
3. c64b51830186afb44384579da5517996b6d2b1ca2795ac2d50b4d93bc3140418

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.