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

1b649b3b7783064004fca6efac886c4024809def28fff980be8303470c9a057c

Seed

79478241b24dd9a0ca4849b87cad9ee1b855fb8017106c059a91eff213373fe3 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f9138316b91a3e1bc64fd2033ef3a50e

Commitment

Batch 60,230, Merkle root 31e82c6955dd5e935ad5ddb2389165a91ca27ac652e39bd67ea6b7300df7f313. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 33ac0afd92b1c4643fedfcabc22b1cc2d7deca25d61bd068763b06300f79cbb0
2. 5594e332b6734ce1f8ca18ead44319e677114f6a1ff01269f0ec113a664cc2cc

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.