Redaction

Rewriting a memory to carry less detail while still carrying the fact.

Why it matters in a memory layer

Refusing personal data outright breaks the system — on this course's corpus it drops a diagnosis the exam requires. Redaction is the middle option, and it has to be designed per kind, because "less precise" is not one operation: a city is a useful address, there is no useful half of a phone number, and a health fact coarsens by dropping the diagnosis event while keeping the condition.

Some kinds have no middle. "Sam is a nurse at St. Aubyn's" stripped of its employer is still a named person's occupation, so it falls through to a token — keep that something was said, keep nothing of what.

And redaction changes the id, because ids are content-addressed. A redacted record is therefore a new record, which means the original must be explicitly retired: a policy that only adds the redacted form has doubled the data it meant to reduce.

Connections

Taught in: Redaction and Minimization

Do not confuse with: Cascade Deletion