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

7081147931c5ec604ed3e45e487d4fee7e67ec2f32b978df1578457cba95615b

Seed

b3474d6cd0da8c5e69a652e9b6c5a22099e4ef53b5218a0d2708e89ff441bf8e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

758f060cd109d0f53ec2fa715b7d693d

Commitment

Batch 47,854, Merkle root 6eb1e21dbb2855e890a4487e834c35f90d8b26eba360c555524b468653da0464. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. d0fe325b656bbf76d929b55dcc1aa167fb9c7013ac462b12f15669a5a877c2c9

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.