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

87711de84079ea225b68b7392561a1c1480ade5b17ab4e184ddf4e917e0730ef

Seed

da0804bdcf00aad983d4e060ec1a73cd1b15f6cbd6f1086d6bd28dd1ff0238ea SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

97227e3b101db5eddd4992e15a79e428

Commitment

Batch 54,084, Merkle root 6711178f0836541a6ce397302a6a59c53d25987753bcef44fda25f7dca9227c7. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 0f459d7ab12547266db7b7cd2e841c7708b0a8feecaf10e4a8e198d08f245b85
2. 71dd6204bce7749a16aed32105686e64850caff0e185db053988adc0b1473b1c

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.