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

7aff3a5937cf82e7531545e5803b82a62698f3588f549df33760baec10787eaf

Seed

f5e892d67f62d3326d4b977412daf2f7e30aa8cb6023f0dd0f11ec9ca9f07d50 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

40aa08528452f91ef485e9defbdd3053

Commitment

Batch 57,268, Merkle root a03c5bdd2810dd1fcef0c1a92b634f6e61963ef62dbb848587ccbc80d82c46c7. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c058729f1f55abc7438bf4b7ee3f5fb92fb7e91be930eab87975299f910165c5
2. 037df01c4085c80e411a353dc9b8cebe9f9989b18cc493011d24acda0cc6c113
3. 3a0ce0bcd7c3c2c01242aecbcdfd477cec87455bd635f908b8fda2416f6d8268

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.