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

d149bf1c925bd7427ec93fdff29dd80eb87145c168bdc89907cf237fa7a3c9f9

Seed

25bafce03c1f8ab4d8f95314bd96955d4f3cb758beefa6d36e77a4514500d940 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

6575271adc8bd9f551dcca0845b9fb72

Commitment

Batch 69,257, Merkle root 4012ec7d9cd06d05fdd0b49e78e8ca9a32c8f6ab3df1e7354e10942b4be2bc84. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. e91fc2437ace1c4056df522bd5cb2ce8d8f6eeac79a4fbe0883aee7a948ca3d8
2. b288ef9dccb8103caf5ccf23b09076941bcbc086de6102324bbe84dda35f6a9b
3. 36d9d6e9805b62b5ebde4a37b62d69ca09105f936e806f6de11863e8359394a3

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.