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

c94791399ca80ff51d7ddb61e40a650e6499a6b92760b2e5d1ef6aefcbaa7e38

Seed

be1a7420711ef2a1fbcf318a29179bfe0b7fbb7551407f25dd21a60db1b50e62 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

336ef4300206e56c7cab7be75d4db3ad

Commitment

Batch 61,373, Merkle root 4b2e51873f9a9d8376ff550165339d63b7b4485f0f8219c5066eedf89d9496c8. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 4a0712fe41e03b691b37f16041f4e20ad9995df644976cb8d35fd5bf056e2e82
2. 8d235bec5db93a7607d5ea886bf05a89d500e43818932a1f019034d01ab17fcd

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.