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

9bbb45dbf3189ad7f1b64c3902f5cedcf8c8408ee8c59d057825bca8f88d5ea1

Seed

ce22fb836ca408018e76260fdbfdc1b99a2e4ba7ba2d9c3eb124038278c27176 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fd8b16747e27f64104784818030450a7

Commitment

Batch 56,051, Merkle root dd45cc967cf4ed06eb750267250080e56a69334350a800c228e92081f06cb3f6. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 245cd16aba710d7ea27e0d7d66ed23b92fd6e71034ae826d5e063f1046bfc5b9

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.