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

7af94789357c461bd3b252db3c324e4df20929be0a311b6095391914f07f142e

Seed

e6ef4a237d13e6ac58b03b9c01c662283d62a430a7d275c6aea43ea98689c14b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

60ea9c88391ce3debb050c983c5cddcf

Commitment

Batch 47,816, Merkle root 011ff4e8295d22f68621ed4aa2843a8a6cb2a6cd8ce8c8ac5b5c8db6fd713b8e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 8f26fec584af1d7757c1198be94ba8740e9f10ef2087fe589f610b44770c7fd4
2. e3ca49fa84a13fc804c9650dcf65cb0b3106346654fde7176a50afb0494374bb
3. 2ff182a593b06925d0bfec4d68563fb8b99f302eee43934a36c44e0cda34d88b

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.