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

f838d1d0d5aa3001784d2910394af34a94d91a8eb7c39b29641a2afcd9217f23

Seed

34dd278efe66af4359b0c3e883eafedc3ffd48316556e8d74d920a12022a52cf SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4c868d11ff4870e6cf5c3893c0826d54

Commitment

Batch 69,554, Merkle root cf6a14c1b86a915ba1ba30dbcabd81749f0844610c6eec0fa023bc82df6ec06b. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 6722370a6b98644b7c774a2a57ba3c6d29016effb53c57a022de2a58b212c3c0
2. cb9e9dda73c5f07df5725d44f51543b9cdd9853ddcd896fc60abe7fdc46cf642
3. 8bdf47c838dda4e337eee46744d6e1841cbbdd4c8248bde024de241a5158f774

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.