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

05b58c39f7cbf062d3bd8520d883c3860cb3103c27113c77898c88288d40af06

Seed

e169674b0c52a3aaddf49432e6229edf704136231ffd6b8cf2469999d9204ae9 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

15fb9ef0e030ec767db43f57fb338daf

Commitment

Batch 55,417, Merkle root ad0936dd6758d6e4ed68ca5a7e3671b62e48f334c578ac6ed2354314251290e1. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f769a7c7616a1a3707d5d73de8c146ee920c8a04559660bd8a847654cd2740e1
2. 04c627cc3d9d278d51cdc4ef647ebe35cf89d930883401c5187d0f64f082e1f6
3. a401b499f57eab7b7d706d94347440c51092ccece0b2f6fe77237f08dfc87a50

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.