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

76e476b7dbaea96e438c204853ec9c65d39baf4533a0ebeda3b19daac808b9e8

Seed

35356936c1f67c347a609a515f52db1cebc0efc5957d660db8df3837c3bb3244 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

8216bd3993581635e1c0049b7dfd6324

Commitment

Batch 60,503, Merkle root a48e3a3f1d3823c6dce1d58cff729dd9cb4627a7ce63a10729f94b309cab531b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 0181d5e72f134924ad6b4014e49f0e84f41eedf50b597a7c22f09f96bdf78910
2. 1a1523223984fc790187191b96cd2d3d8ee02fc5b30812ccfe8941aa7c74a014
3. 959714a656377351fa39ab313a0d08b3d1a2d275f4b690025fae523e5aa7ed08

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.