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

0f247945e54692c0364fe4ee121f9acc3034305d22d5d65bf81249e896aff670

Seed

8490acb241c6c8102037822242dd03e5037c55b50249dc833159990cf4797be0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

7189a08f20b64377966a4765224b4dec

Commitment

Batch 61,489, Merkle root f23bdbbaa070c4bbc5503e9917130ea9c463745f9fc3841ae4b197d461d71300. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e31d65253ae06b25269506de66fcf4f7b8bfe37cedf584d34554c7b536b60eac
2. 651ec4bf611f20488f83e4f8590040ef6e42f627ecd86a984fc2223d0680e627
3. 5f180db96cba5a6d27c4c6424a75d5dd33a9ea91f34966307199e2e66f5339a9

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.