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

483280bc1839aeae3ecaab3a4ec1e16f794e16777afc8235d320171a571b18b0

Seed

41826731b91bb162f2f100412ddf073dceeedd8ca3cd6ddccf01704e09498af2 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f8848c912b3f20ea8aa0f09578bb622c

Commitment

Batch 64,459, Merkle root 3e303ccadecf57e05a28bdc31927487c42c4fcdd8a6f110a8defa7358b449486. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 4171034cc7fc7014cdc2544e0147468b8c54cb1349ce26c5c3e614ec3a0370bf
2. 990df5dfa8dace01b6474080a0ed8ee210b33f66fc1fd7742edb12e0fdd24120
3. 10f871c6a360bebc4c6f0ed369aa880341d7825287735a97e4ac44326167c6f7

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.