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

ac0fa33e7caedd68098ec80d0d0f95c675fe33add4dbaa7c11dc81d612a672c2

Seed

6296732d262d6fcd906e03a07b95ac3331fb2f4607d8f525fe07d33fb9ef73c6 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

906bfa5810132d6fa00c58a6b604ed55

Commitment

Batch 58,084, Merkle root 71982ac37343e5f09e231e31c6bc981491cc7eb23cbe493d3b1f3f6915af65dd. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. d9800d2cc2e2961099f2f83a424bafa9fcc1a5e34fbe380515be5b770a8af2e1
2. 542ec0511f52170547a2e2aeefd2c418394570feca8ed6b5a9fc88867e7def74
3. a09ef676fd8aae66722f45cf55cdda217bc3010ec94cd1441d747f12c3beafb8

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.