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

33125c688980d27cfee823e4dbe25fc29ab955eed346016fc7d628a64ede9b70

Seed

c898c29a676faec86ba41d4161d899b395f96211e3563a3c10a3fc23c4255bcb SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

399de11f0a64469278958076ef405f51

Commitment

Batch 57,140, Merkle root 0632357858562b4db259ccf4a446d31c878a68909125cc8e17a54113e44e5095. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 7f413558b8be2c4aea3c998be40610e6f9443205e0a413f388117b61714f7c73
2. 09627fe438731ddbfa066d2e37d4b3835055fe897fc67f0cbf1dbca93c55d345
3. 597b295ea90b55f19b7141c0d5b94e9328fe0aede7f92cb27b86f579173ef322

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.