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

413a74ef82b13dc24e7989423ad77960a23c43a7e2cfdb1178ab23d7182af557

Seed

cd8fbc116e3ae1f299422b11b2742f7ffc308f5cce340186e1e131e63de38cfb SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f56da376ab47571ca2e35aef68fa5aa9

Commitment

Batch 50,623, Merkle root 39318acb5c619dedf3738ae016efb1000ffa272359c44dec6ff775f5330a2107. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 2b27bf28a4d3807c53aee413cba7981c0bea7227c0163b7f872c121805a71023
2. d27c317263b7176f89fc456dc7ad51fd7a238fb5ee3ed76263400686564681f3
3. 763c4bc2de30887db73b7a61d85ffa38055ac2dfe3a2c5fa6d29206e1801940b

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.