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

ecdc6ab0bed482a3585dcdf451bc0fc39c913fd3da4210207579b9a08e6e3fc8

Seed

27cee736ca8270c1b7b687e3600f96b75ac6cb77028f4c472419b1aedd3e0e66 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

c35823d2c58b0031508864b1ae4d6b23

Commitment

Batch 51,430, Merkle root 0f367ea29135371e07e04c08d0c313fca62d639501cf31a18ca1ac7b74e9968e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 1a49e60e5f3b849310a4c93472ee26720045444525f5054e1b21e1b608956106
2. ce57f38ee8c96c3311e58b98a5e96c2127ff27fe3cf2ba8bd825e35e97d7d9b2
3. e5b8b94eeabfb4357b71b4d9594c9380b955137bfdc3d54f42b36a8d2fd1e942

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.