Surface bits vs effective bits

People say “bits” when they mean two different things. Surface bits are what an observer can write down, which of six bearings was pressed, what colors appeared. Effective bits are how much of the secret those recordings actually determine.

For one character with six equiprobable bearings, surface entropy is about 2.585 bits. Under the Rosario–Wang observer model, effective mutual information with the secret is designed to be exactly zero. The notebook fills; knowledge of the secret does not.

That wedge defeats the usual conversion attacks: frequency analysis needs a skewed channel; correlation needs stable dependence across rounds; keylogging needs something reusable. Burn closes replay. What remains is undirected brute force against a rate-limited ledger.

Try the visual ceremony demo to feel the six-zone round, then read the longer Observer Bit Model page for the equations and parameter table. Absolute product claims still link to the reference architecture that earns them in deployment.