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

63fc16cfc7850cebd7aa2f3a783971eaee6532de372ec3a2e5d00d81ea69e118

Seed

d02c8cb1cffcd10de34c64854a592e6a1fcc6c99c16872f2529a40905a1703c9 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

893e4a9e158acdbac2e02334dc8cbaaa

Commitment

Batch 66,751, Merkle root fa87f5e00ed34e93801f05a14b00ad6dad0db2924d6a76d969c3466301a37315. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. d45b879bb31da2f51595d977485bb7b249a877bf34128af609c9bc21e3400652
2. 96e2d74a0fb16e5522d283f59599717b3bfe37bf0f9058bf0a09957c7f4dfb15
3. df09958d39b4de781954115ce6ed81ab116f3ace41324177af33003c28b4aeac

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.