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

7fee57bf6f1590c9a3e3c5cc47b8f5f87e246bae414c367b00afd0cd1969a730

Seed

68a73d59392d859fd40f9936458b60fd302367cf3fba3ea50fa332b04e2a48d9 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

3f59498646f7e4a1b29e3933c8c2ebb9

Commitment

Batch 53,384, Merkle root 77f8ddcc7eea65fcafea6fc786fb8039f5c2fca1abbf213278afaf3ad60bf38a. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. ebec4c0512443f49b438fdc5b9762676b1c6bed48ca2cbea7a5d86beec2f8ca5
2. a3d159600d7681002f25e0c3ff7d9f809975cfc495ed46cfe50dc139221725de
3. f4306b7a26d549d99514f07ba787ac135a6e27ea8b6b99c11a085d9785af5006

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.