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

e7f0b1b9e2db1b47bc7c141f679c3f46873b2ebd80f8b27207d49a0d68da97a2

Seed

4714034ca283d0eb95d2fcfad31fea6faea3594c14eaaff369783901ee4bd41f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

cafdc24dcff343c270d54deb27c2d9e8

Commitment

Batch 57,697, Merkle root 8033e57ed74f6e0708615ddd7603b1dcc58e05d79adc1c0534c3008734e6c90b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. fe41c2493841fcd4473654390ec0908bb06dc5165d8840ae59cbcd5fe07521f5

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.