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

44d9288f51a3245c2a5c1d415d061019c533ae7f06272337607a0813fd5110e3

Seed

e24b302930cbc8a84e929da622e7ae33ff02acb4d33ee435ad0c09bb51d8a808 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

e285e03f59204876264886dcc75154ab

Commitment

Batch 49,040, Merkle root 920fcff426c43c1fb456ab4e037dbdad78be2936c1fe770a6fc5e8b271ab6faf. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e474045af92cab29ae0f89f6ce50f6f359628f8b55167296e839c15816758eb2
2. 50b49bc97ca1d58b7aec954732814b84e3398df13436b83021be78be7064c88c
3. 0119d5f710b41476988b62c2dc24091c9763f23f7eb7661897c39ed17fd5dad8

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.