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

f09255fbf19994a162d6dd8a63a37000781e9ebea85de4ea5de3b22c12d8e166

Seed

78b126ac2c2faeee994fbd30909153fc68bfd0500c43a87cddf52b63c472ebec SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

3e6165083e6c22107c03e21e4ab723ae

Commitment

Batch 64,495, Merkle root c551ef2b74ac06cc856ac15a107ec78d1fb22a76213cff06e4640ef824aa71da. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 460446a5e12fd84b38d98e58cbc253ad037bad783846d02416cc7a38d32f0ed8
2. b58fa17ba8c58e9c3435ef573d26fa700eb66951f3b83592cc74e43137b3fab5

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.