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

0505f417689689e34346578cb3ceb50a191c7b6dec220bd788f68a681095493b

Seed

83825528fc90c07bc4061d0d61bf88c5d31ad596655bc81eb108ba8881775d21 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

868645791465d62136d1202d360282d2

Commitment

Batch 73,567, Merkle root 8d12c3e3189221bdf5a78f8392472123e9ccbea3578a5c0666aa8a81b20561f5. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. b4ecca0edbd1d1c3beed35714fdd6ffb256cbbb2d36064f2a27a7f11661b724b
2. ba1df10dff67c0b1b93cbd5f3ab01c3a97433fd7f36dd2ef6d503ece05237d45
3. 34073d341617a646ec50c54fe1f47b6767b3d108d54ea84d12393b4931f7add3

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.