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

ef0488b484901fcef400b18bc4522b81907fd8cdb4eb3343ec33e793651b60d0

Seed

2fbe2f61f46ac204bd1a6aed6b2327326e3762302205ab0bd7985e1cfb7f0142 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

cda21c34e7e2c6479efe67ccabf7f79b

Commitment

Batch 57,039, Merkle root ba4493903106d32a84f058cb8cb75ccc4547078d9f10293d1759b6e6e1a670a3. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. a542a7b1f8532e1c8ba2a9f675ab93407f58e8a43398264822e0235cd7e222ac

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.