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

1d37d3505dd75e1259a2a36313fd7ac71ef640662b016ce4b5ed9b792f227b95

Seed

f7c53708f98d5115c27f32d9debc7f795a6eeddf6bededccf4c46ef5e23da41b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

42094fb9fdce658761c1fe6140a703dd

Commitment

Batch 70,172, Merkle root d2e9398f6295272cf43b92fe850d201ef02a0b1f295f51a82f47f2628f90eeb4. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 9a86c09f42f2f26b627157bf695aae355804657a72bcc88c05cc89d9c75e4c3f
2. b807489412ab65a09a4b55d0f7d385ae34503eb07abe24ad3320fabb88070a6e

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.