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

672a5b55af5e1a906dfa7236f345a195c61413db60c4715c1c1748cffef8de27

Seed

5650437f50ecf903f244fbcc4c3f4bdf55b3ce0f3b27b88b93276697fb1c5be4 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

27e3699ecf7d0e05cfc095b6c084905a

Commitment

Batch 63,567, Merkle root 95f33e6a1bc347f1784c61878f72131d24f143fb5ffbcb18acad58fcde8629b0. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. ceeff02b8e3323ef3c0bd77a70e5308452c6d8991fa7d85bf39cf75aeafda516
2. 3d8c43274686018e1f0ad20a19719bcb6c5e824c7c78ea46dcbf0b345e7e739d

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.