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

53d8bcc6fd0ccf1c852c0782c2422ddaaed1c9918ed70bb08f1f254ddae23be8

Seed

dcafde8875616d7e061a371327cd9a52a1436bbaa7e88b1c5cf986844920d8b2 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ce52d60dadc4ad62df3a021ca353b516

Commitment

Batch 71,826, Merkle root 08d9e20120b862d0a985479ff9f9fab089cee70ba441d9e3b7ee4b1e293ba24e. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 67c0850acd7e046684da63b19408d7c57b2e4e4384858174f029ccb9ba46a0ea
2. 39992e00925c33891fc0322605f61e26b0e00f502435f494919ec1e96bc62040
3. 7c77c55bb55357acb251302199f16530690421cb6093116607d99b8e7b169497

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.