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

2a4e04cedc69e095ef06f97ac8c76e7dd11a0a0599fb7fe71e6192479805fd23

Seed

feb8addacf6e701f72f7b0a375081ac1c165ec13a3def2ea01ac29391403bfc6 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f721c3b9e4eed783c1ca1f9f42a62f1e

Commitment

Batch 60,679, Merkle root ffb0cf153a1e159cfbe8a7dc44703c9b387a694b23871fe4cdd653ede31b1684. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 135dcc04f1f3dedfb4e2ee97a9a1e17967c9362ce15a1b616bf60bd86bae81c1
2. effda0f903c0043e0aab3bb4cf7a57a53de634da461567431674d9be77012f74
3. ebe18cd8df2b3495dadb854cf51f3c8ee695a650eae4e2f3fe855a1850075aea

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.