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

c5215141813feff2eeb6710244de2f2e735ea90a40dc98cffb1fff26b5e0b4c6

Seed

bf9a3c82c945a6f82e73c071649643aa5d1b90e49c58c08750dc89582cf39e9c SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

a819a5d390e47a4f3ee69ab82d72a58f

Commitment

Batch 72,859, Merkle root fd318da70f7e0d09ff19d2d20de2506e7d8a7fd44a80f1ab3527e5ef9e42516c. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 553b3525c94505c8a879cef924ec2c80a4032eea970b63527d2e36e9956cd9dc
2. ac832969d24b00924a6aaf308b750b073db12a4ccc82b71ff8608a37d6bacd26

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.