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

11fb8d8a79b574c8f2260c02f796cd39a1d1465b28b50a2b8f4fc94bf9f89551

Seed

7b51dc67d013924f5166f9635b4ab312e82c2332e101b3b7b3fda81e98a697d0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

01b1a823e523b7cf4bb181cda9ca3f49

Commitment

Batch 69,902, Merkle root db36a02e05cc45f725c2d1084beba3d100d9d7f9655a03ab2d5c87f3a6016724. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 328639adaf951710467470ff28fb2d4762465c0a9378132425781df44fc21825
2. 5dab1a003ed9e49c36ba69e5fa203c8ad060379f3e53529a4e420365933e0dcc

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.