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

88829b58cb08273cd9ffa46d6838cbda2dd57f67529ce1092dac8a853dd1118c

Seed

a7357d4d7d0f6b924a217a025feabdd95a992651007d0fde18adbd1a96e47983 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

71888c7555d8ed0d2cdaa4542e222fd6

Commitment

Batch 71,890, Merkle root 3c4af1df4b1838d64940d60c70dcfb0123637a5eb9cf4ca2eef227b7d42e7344. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 780ce78a72c71783258f54bcffc2747ca12decfe91432823aec8cc848c678434
2. 4b2056ddeb264b25ac057e464e0fc70343356c17dc469b77cca39bd66e3b9ac0
3. 6c51316c20c92e69779f224cf5935e3ee4be892bd3927f047288f2bf59d694aa

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.