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

621a84f9fd348cddfd18f2a549cd988bc523cf718c37093b6a67ede3889a2c8f

Seed

88d758362f26c9fbab3d3c2825a3975d9d6998c9f2a73af69c459189f0df144f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

c90c14c7dc38d5f0dc785d6037cdc194

Commitment

Batch 71,480, Merkle root 2800ba3426103f7b1c6af4d147c9388452ee9ed8c68b87c474f8c3b1d5dbe11d. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 2f069ccd7dc412d25400c1a4e19e56a4b4cee2f2d2bc4bcc281c3c2649abbf60
2. 358f6d941399455d62cdd8a8cd97ce9c5cd6d86da959d98155efed0435521afa

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.