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

fc47e7759bc297f68227a6ce35bdf29db5429fde9b92e2095e19e9f95d543ae4

Seed

4d0639f2681879996f6367b5f92600632ec0c51d2dff9cbbacbe54cbffac4aa5 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

eb849e4c473010f20e62fd71bb362583

Commitment

Batch 50,270, Merkle root d7e58cb692b9b6a638885cb381fdf77fb475d76ab279802e26a6fe57ff960355. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 993808441c86151ba917955d4f46a2c2ae03d8496a84c9e7b62fc44260107da6
2. cf867d8a489fb7e5bd88a66c9e346e02744760eabdcf6f7151c0f37188f9745f
3. 3cfa8e0349e95ef2191df75e6300d7a437a5525bf4b57e86c12f670a76adb92d

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.