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

cf4845d3f6851896d024641b1360fa9479fa365d1106087fa375946169787679

Seed

6fa8cbad7ff744de87669d5ca021d7d2be66918dfa4fef9d7a159debbe9631f5 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

97f3fd5f0ba536ef981ba8cb094a7369

Commitment

Batch 70,084, Merkle root 0d6465bb34e66afbde0e0ac595b19019e7d372cf1630a9a3678792f415fcc2ef. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 3aa810f0d256d4f0f7f4699baf4f492f6c5c9830e40338da3996ea254e8045c2
2. ea568bfba235f23c4ba575068fb4fc31d2504582391234c11a1b579f591ebad4
3. 54e4afa52ecccc35e2f7c4f33db70312cca922d672f9d4a0c5ce0d17f4d20499

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.