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

58fd86ce271900910b0445f3eed353b7fef4297200c038e4640eaea3d579f83f

Seed

e5dcd9b30e01d41d4247690093917f064a19ea5efdf7ef89ed2ec44507ce1120 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4e9577bedcf9a10085f9efae4fae6f50

Commitment

Batch 48,290, Merkle root 2809bdd3de3d65c2151a791c4b4a1b4cd6e314f6fb068b824177c76b18aefd7b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e0e30bd022ed71676c27f999fe5a2ff4b3afcf1fb8e6ca62d0e5049b11ce3231
2. c4723e3839d2c5549c79778fb546ae1d63c6dc35ae2e07b45ae89916470c6f06

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.