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

1325fce306adf81ffb4f6c92903cf4e7c50b3a3e152e9554d22fae99645876ed

Seed

30939189f8408fc05801230d7fe7bcfdcfff62b871370abde115979c939de7f0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

02d6ef4da44c322b1b5307691bbfbb9a

Commitment

Batch 55,065, Merkle root c4c353b961a1f6930382eef46aade3a12eb6be298e9d6199196801c5ebf3a415. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. fec7b7760dbcddf45505de0b792db229017959fbf974e330741bebf226b706cc
2. e5fc626dd157c325c78bdf445a836d8883adeff77454553ddb675f326795df6f
3. c1f85f4c12c79da0fe39650248122fec988a115879c3bd4eaa5748e1d9a31b7b

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.