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

800691bf9872f4cf90fa903b304a7a4fae636d12dafc820c3176086c1a5a1363

Seed

c655c868a3989a1c3e0f3fbcbbc2689333e74e3e8ac9d825ee390f7c71f1898e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

64dfb62431e058f4886ae031a1bf4828

Commitment

Batch 70,847, Merkle root 87855a418742e52689a9611e568b7d130e38e40a97d7538dc09d9bd41786e8be. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. e339e98c7eadffc58253e090f8a36ca408aa3ec53822d19de822f3f994948440
2. 87c94b00e64ce41a6c5bd70dab3b78eeb1a69a414006ca467d5f41dd2c9b4c32

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.