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

5521ff815502ec45b054dbe0ac2bcd68fca13f1d6adb93bd693e7d240a1888c4

Seed

cdc647fea3f7cbcf2e629112310a0f1a4fcad282ec8806d6dadb259b889aba69 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1ef76a2ae411de029d64df0596fa7d87

Commitment

Batch 73,271, Merkle root 862dd2294a24099e6d2fa798ee0eae4ac0f05c5a0ea304e641c4bffe757888c7. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e472797817ad6820806b2286f9a188afed47f59463fd29bc2f4c85c053066af2
2. 2bd4df6e60041549f127986adb52b94d483e90bac763451aa0e96abf02dc2db6
3. 6d035df2d8d870f1eb63a1631a1813ce272eb18795a251bca3a0e98931c0f9c8

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.