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

1d5dbba1191dfd290ccbd1a5831cd7be8a43f84dd1c28d537fab123d9c58a3e8

Seed

5928873fd6324bc4a78b5f04bf6baad20311bfc6d021eecaeabf94e54f17c0bf SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

84e67723aee7fd6ac55959712d90fd3f

Commitment

Batch 56,643, Merkle root 8ebfae0b160d77e59fa86aabe91fde98429c3b3ef644206a0200987585aaec97. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 2e47479a799de039adf763432326a5a65bcf6ec9f0a23c3ed0610d1118bf13fb
2. 7e05a3beadbf46eeea8c5e31321577019103f19f1fcc221df7f48c2757890936

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.