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

53eac59d535ed4e8a16937b7109c7ec152efe247aaa05cb1cb67aab77132fbcb

Seed

109a7f9f7c4921a04ea4c59f4548f9cb6760ef85ce0c8e2a9facd42fe48ca6fe SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2d48114f9ea347ee19016e0eb9d113f7

Commitment

Batch 55,313, Merkle root dcb74fc567d505777759005c5913de5bcd28f6bfa2a7d21d0bbbf2288bbfb4a8. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 072772113daf4570a9032b6887adbc473fa7315fbb661d5dcd20d2538c8d1b19
2. a98ba78dd25532f729efc62ca80bbab5e2c0ce52c60ac82d48d266d3f55280eb

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.