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

83334c95b0eb98a4bb404a188c31a3333f85dad1d3b32304c01acad3129f33e3

Seed

846e3e227bc685d44b5b11f0d998d7370891f6820a60c65d63c91241ba159b68 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ac4733eb8b5ba58ed16fffda4e304ad0

Commitment

Batch 48,407, Merkle root f7786090817bee93f5c848f165d6b6162af963cb6a73d111198e72d21ba1bc83. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 1958f3811b5fc4fcb75e90d5e7f8598e3e95e552a50eb6ec1a97998db2d1dd22
2. 8e5f0b3d7dc6de84a03904117f3d9581a39463f53523651c9d9b74a155d27b30

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.