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

7446e23d4751ab742290704351765f1677343a70461a8199649961ed28e123e2

Seed

4341179feb390031a2499d38cfc23a9c83bc5741470037ceca30fb4dfe3e387a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

a89c60a35f699f69efe9fda5dd6a6755

Commitment

Batch 71,710, Merkle root 14cd4e71e8b0cc7fef4915ccf27c88091705663572dbbd44c84c19864e7b21c7. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. bcadb0efccaa27bb01bca1af1a4c21e9318ba4a85f0eea1048b015ea2f02839a
2. e4de39a81f094fb77344f22429a0500b2e980be941f1eba12e9e302dfc0da7bb
3. 205b83e5c97d6549a7a4fb0301d9b938534d64230b74f2cc7058b32d1b8a0194

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.