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

74219d6cfa6271d453c45eaca005f38c80521918452a1fa4385412435f930a91

Seed

889ff153fbff6118c4d2042100b6bdc6095d5befc74b6a4eea1222d37927e31d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

a1ec1d3b212c4e8eab3241bee79a585d

Commitment

Batch 67,814, Merkle root d2572db41a653392a81399ad102f47b7540a065c75302fa559077c29cebc70f8. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 0cfce7061949dab073d9782383a170f5b0ef00c250b88d68485390234e6c89e9
2. 68f8f014ada39343b65ed4dd5ea4d4ddfe5aa55199fa4a538e0a847c0f0b191c
3. 0a018ddf4fd32ee96a046133c6dbbae837b93c911c2d5404215bec184638dce1

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.