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

a1af82379ee78b75c2436ec1ed9195c0542425d44359d694978ccf0a02dca467

Seed

6768f0b3cfddb93e7e5256c866f007f6f80288920bca93d2c7c94dfc757476c2 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

c11a8801da3a8ba9e2c44ba338c07c8e

Commitment

Batch 63,119, Merkle root ba2d417dd26a47b919468ef45918dc816e110eb5bf129fa4068a358a09baf157. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f9d1c420525a33c45adb7d99f7edb286c8a7d8f7dfaf80d315ebb6c6809712d3
2. de36c567d5f748a55ec0abe6a2fd947c6c87e87328d240905dbf94892d4ba043
3. ff129941a9c1eac59cf271f31a56fcae591c53ad3229236389a9a9a2d27380b1

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.