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

0f17e096f09fa205bcdbe3d3bc1f7eb1750f2a2116993f4f083623037f84abb7

Seed

f587cc657863828846f7414d645d90b39651e8cae432f5dfe537f38a23a9ce61 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

102c55b0ca16fbc226fc9e6f894102ec

Commitment

Batch 68,916, Merkle root 47ad685d9c2ed71d2a78f870dc66228455a7bce9112f323e4163258465ae31a0. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 67011c928eaddf4d45a5faa52faf352248e5a3f8d3802a94eb81ef1be9fcf23a
2. 380272d2943e1017712f7a59ccee349b1c934f5f4f3ddf564c961fa59454e590

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.