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

40f97d70119ada75870129a87503ec9f73a7b6d41c2fe5474a97b5d90f9fdcb6

Seed

b4f4b0d40f77b35c654c9303f9ca755a6fa702d1252b7817ced358c19e62ecae SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5960e6870a468b4b5b81a088328952db

Commitment

Batch 47,935, Merkle root 0adc68631bd83a82b4d3db6344e908c818342c093d7ad016796fcf06e88971e2. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. be95b60e10f4736619f255cca5e7b691388c0a5615e827647e3d76ac8f17167f
2. 8ee1fa3eaffaf55aface909393bcee5ed3cac38b2e508a64f5f929b9ef1bcf8e
3. 8d28137b90391c8a8a35d8048c90b8de4f427739fdd0368ee9c0d3ba0ddb8abe

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.