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

dbf4ef05933811b199bb65fd952a0a69846e0f6c811571e196ea8a1d4f2c41ac

Seed

c32940c2bff5cad004c1460457e32509e74d81ee14569567b269db0af5305b87 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

dbe71d0b016614c5d8334dcbdded03c5

Commitment

Batch 56,454, Merkle root 8ba27e483ff7c9702f1a9501dd63ccf969db9807278c4ad3d17e927ec06a5bd6. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 8bc1ac1a5a569d172859f677e68f313f01ec0acbcc35882387df1d9ba7ece8dc
2. 6e56e16c9b9ee2ac8910af2e43fcd0d7b4f45869f5367571a1a39df2950f1cdd
3. 6c7a633d9c4415e52bcabd2618442670a2d1d34f03d7b1d630002d7415131ad5

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.