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

e826525bf367aed97f151453490f459b50269c9f3c910d58b0be0a8f61884611

Seed

f843033fc8f14c764773a956256d8fa7a7629b5cf88c97690e564738867c1e0f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

60c7e12e8985afe52c6249d87f10bc5d

Commitment

Batch 58,553, Merkle root df6b7a79fe07fa0b74550f23c83e51a19b4b336adea42e497b1fe9fc5358acc9. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 25ccb1188ed61440ecd2c12750fe8b6f4f1a6e6624433abe5212d76f7b0f4dc7
2. 19bd7021503953a4461652444c27accfc2c58caabddc800f56b6a74362949076
3. d8e6697f2ff6a4d58c4c7c278bb969717df8a0a3cff4a939fbfba358698986d2

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.