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

0f19c22219f9a25db70ca9d28bac53bd7991bf1efddf0fe9233a4a9b979f3567

Seed

44d816beafd3396bfbacbd31275750e34496f7b5e35dc0f39e2259ec30e4dc61 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

cd9e4edb8d1b14ecd208f6fe2a9a6869

Commitment

Batch 58,648, Merkle root d0aa1a270b13c5bade5841bbc9922d670e33d9f9bdcef7d5c1773319a86b95fe. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 44e8d26ea79b68318520fa2cdd431d784c5bd18323186d09b0aa474b0aefefe2
2. 30d2cfe69131c32362a1a27668c97082ea9333d84626ef872fb2c1ee0ff40f36
3. f7951181f6544dfaae48cb8f602151c62eee81124cf65c72fd79f86052bd61ed

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.