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

0fa85fedb97f95afc392120607f70c001120898271fce286bf80d64d71509285

Seed

dfa415b431625fe132881369ee82c9b5288ce028d7f197c85cf7374d83f42703 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4c0a2d4272460f65aca7623c5617d41c

Commitment

Batch 65,189, Merkle root 4ed84de99f6f90e9961f364290ae6be3a9e27d24a84e31dcb5a1cc56dfbeded7. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. ffedf7b733feab3d198cdad8dc203d2bdcd473aa6fe37df5f6a092255c959b0b
2. 0661ad8b9db289c95b6f30e42376d062a5b3b8cd7e293854608cc5f232af1e7c

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.