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

a85904d03b73d4ce159bf0ba425fb0399edb8cdcee56497d72d04e612fd3d11c

Seed

0a55b909143a62c8ad4bbc716e6901aca06ef6078c22bca2b7c0e319db117231 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5c0de677e9559079a7d68ad415c323b5

Commitment

Batch 65,189, Merkle root 4ed84de99f6f90e9961f364290ae6be3a9e27d24a84e31dcb5a1cc56dfbeded7. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 61cfecc36a82c021a64fa5aaea5086696ec2e5907d472bcf0d061802d02a66e6
2. d40fb8eac22ca01675d9eaaca725a1e38f7f814a4bd161eb854c899e92602f50
3. 70bd5b32559c074440f6b34011c08c30de59b402aea3f3c1859aa60350b4ed44

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.