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

5bc3f1586d130a8c3e86093fc5e160839103234578cb5c51a5e2a8b541633ec3

Seed

2a2a2e016b7e84c9dc29c0f3232a448c1892a034e2464f69c71fd640fbb0ef86 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

577dbc3e0249d8b3bf7e37f656b48f9c

Commitment

Batch 48,338, Merkle root 1148492e402c0873852a226a7e6f01135c540ca6ee13bb25acbb92bab61df8b3. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f6da824012c122659335e14886cdea141a29f781827b2892ab3cc0cf04911696
2. 51ad02fb826b306e7298824bfc81c8fef7236454c7800f9e5cfb23e776f40876
3. 93871c72def95ceefbfaa736213b9789be87e739c0df8a047222f2772b284dcc

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.