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

6d0e571a61ea17ff8259e3116a577c2d0ca7bdd8430c9716fe1a156fc077bb34

Seed

1051de4781803a2e98a461e9755af1b15bffe78b0dd40834a82ce971968026dc SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

bb269bea4099a0da2bc306a2b51e57c9

Commitment

Batch 64,067, Merkle root 637ec9dbddcaf815c8a76e34bc87780b1f9b73a53fdb31511a5ead7f461d094c. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 69231aea7482f250e49beed38940e759a5354e53276b5a88019665a0d6cafd35
2. e024a1f67b86710c44b7c34334907e2723ab71433e0cc26bd7595e426cf01387
3. ded03c1410fc149d9e0d264f9e586b870c1ea19b46036d3537302c5b084b91e4

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.