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

ea6b0ba4d6e0313cf3d60f06b2f5b4b7e7383f24f7f06b82a095bbba9a321ecc

Seed

e37c7631e0ea0a901ae4369f3ad9e7366ce4a535ab5c2b980b6d16f9fa4baa6f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b5305fe148e7100a37731ce32e38bcf1

Commitment

Batch 73,297, Merkle root fa9a6e367365e0c9a70cff928ea6377270417eb92af06e0e68598a623c0b4c7d. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. d4b1bd331b3256b9a32e6158e8b9455809df61c374527eb52967cda71fd2907c
2. fad7bd89dfda2e5c681b3327fb03db37907d598cfe499d605c80ffc790aff0cd
3. 0fa71a0399c7611bcd7f1da057de3c72e643512f9f40c9cca51268798b8e8988

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.