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

e7fd52024803cf93b67c8b19676015bc61bc12b904cb1d437a9eb0e5a02a5490

Seed

75081e01ba7290ba3b244cffe3044ec830e36b71f7c4078a1c42e74fcb2d2125 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

97229ce18ecc3c4087539c3acdcf9d7e

Commitment

Batch 69,053, Merkle root 40cb89f2c600d004e799c8573f0836a76591ae6e204c9383675e3ea820e8a07b. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. a744166246bd4c95485cb49773858b77d6436d266c17ce8ad70968fcfb748358
2. 8cdb4d4ca16fb0ef4550823c4d91183fafe57d415183390461ab76fb5edc3618
3. 4cca24691ec9aac75e457ef653a901cd45845bc164cfebdfc309403550af87fc

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.