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

5fc8c7a7c05a626af3631bc54723c10a819677307b670a8918347079b1e12edb

Seed

63a6f9453543af3167a83c2c395bb3979953b4a59e6c81a1b4ec976bcc9e04a3 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

932bc06787aaef16d2fcf78f388d918f

Commitment

Batch 50,934, Merkle root 87d8567a558479be34e5aae2b594c1011a6fbb146ce435c5d267a96eaf5c4402. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e75a0b34349b4fa149bed9027841b70e58fdfeaa7709dc2122eba7ba78282c96
2. e6a9fe1cf8e107c6275815e3fae8cd8392cf32f126be98cd53e4b38f5cb57938
3. 4ac5f9ff4687a1d47388486963d54411a6281c2ffa45ecac72b5b6d1c711859a

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.