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

567c662f7cea581bb57236232506bb2e26cbbc3bee13e3af6b7908cef6faaec9

Seed

c1c319cd8afb23d78639a28ade9464c0f6eb92477fdff17cc6150c016c9c139d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

07b9f5c8c69586d5f623f60fa9551faa

Commitment

Batch 48,789, Merkle root b9f35af4299f2273d1d207da0179dc7d4bef5f1fe1f258128f207505e9ad3c5f. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 43a76e47083fd0d3f977b144cdc12a999a818f0b016cccb01754bb16500840c7
2. 4cbd7ff11d8001f78550751cff9956028b554e424c56ab84dc0943c7e9fa2bf3
3. d7d77a33c3abbd210a3faa8669690a083b29d8ca52698c15b192ae9331243901

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.