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

ddc7c306b67f64f416df595ca42f0a097b18b84f221e8821fa6b7e2c30e2b2b1

Seed

830ae63539dc4ffeb1c801469e6ce3b40ea27c67fabb57b69ba2ae27dfc59107 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

96bd516b77fa190e915ba849d804d2e8

Commitment

Batch 57,862, Merkle root 8c6d6a23e78621b5447b9b715c591ae5920acd587deb66f59c4b73eed69ba214. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 88c6c2b3e55202942a3baad564ec9ce2497f3d7cc4735479aef84bc2c1d089bf
2. ff8b9b3b17876749d69ccd0734c8a9e7a83b6790b1c31d4df7ccab2ea89701df
3. 2a1ce7cfd5eab97731c3595cbc4c6d766753d84de72c1f190c95fc203ec083e4

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.