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

eba903972bbac6f8ec93654f9970f5807b52169c6238a0d4b010ec826ec43d96

Seed

f30095992372874816486b0a57fde23e398ce6cbdb1cd26069f1520176ea3a60 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2f5969da82e4cbca3f6b8551ce904749

Commitment

Batch 62,348, Merkle root 4c409c2a9e46ceee3d6746596de340ae4d5b36bcc463194cd7237d8bfaee72ba. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 4a2c7ef429561326e39f6134fd0c1101f29a4fe473675c890500552d2d9cebed
2. ee24ab17f635d142bc05dad242e3766eda9dad7964209a93d415cd8a22ea01bf

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.