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

0112b68810d67275daad32d179ced706eeef262ab5814f9bc0798d50df1cfb2c

Seed

f6402a1c7ed8868e51df65457f3366a8948d8aea8a5e64f3079475a62add6180 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

dae02656cf44ceb7ec5df02e0e3a21a7

Commitment

Batch 53,656, Merkle root 2dc54290a976e73c37170749a9970c5a9d1343dcfe8f0b8d88c55d844f13b6fd. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 51da1ba6a83bb12a92447e2aa611b8b5dadcf60288fcd2381f80ca98f6ce8c96
2. 4200c201ef3142e1a3fa8ce84c1cb0393fe88ac8a8a6027f34873335554e157e
3. 515a0dfa03ef18e89159a2ffd926768f500799c3f4534df87d79bd8bc187534f

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.