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

b2278ffe79228bf28dd8ebf1ca302d49a8698683bb8f039c5833fb1547d31c8b

Seed

3ceb5e5493c53fbc8e46941853a5aeb4ac3e224b8c3f710e0b129b6adbed4158 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5805e2cbf62d2c0caa1d25746c37407c

Commitment

Batch 61,879, Merkle root ff2d16e035b04d119b01bf7eba2bbec6fe0011a086c02829da1448b9b8c2b443. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 64fed899a1ab191623d8cf4121c03aedfdbe299f7b290fc8160762f40b416e94
2. 5cfcbb9d27529cc8f9d4d7cb6fae5634a9ffdf164049f5df659059cc0abb6d3f

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.