[ 06 / specifications ]
What the engine is built to hold.
Six properties, what each one means once it is running, and where each one stops. The homepage gives you the headline; this is the schedule behind it.
SPEC-01
Deterministic by design
The same input produces the same stand-in within the same key and policy scope.
Choose a scope that covers the records you need to join. Validate the identifier fields, relationships and queries before relying on the output. A key change can change the replacement.
What stays your decision
Determinism is what makes joins work, and it is also what makes linkage possible inside a key window. That is the reason keys rotate — see SPEC-03.
SPEC-02
Statistically faithful
Ages stay believable ages, names stay believable names, and a postcode stays a real postcode that does not point back to the person.
The field’s type and your policy decide what the stand-in keeps. Check the whole record for indirect identifying clues.
What stays your decision
True to the population is not true to the individual. Work that relies on one specific person's specific value will not survive the substitution, and should not.
SPEC-03
Choose when stand-ins change
Key rotation changes the consistency scope. It can reduce linkage across scopes but does not erase retained records.
Set the key window around the task. Records in one scope can remain joinable; a later scope uses different stand-ins. Unchanged dates, unusual events or other context can still connect records across those windows.
What stays your decision
Rotation trades linkability for staleness. Analysis that has to span rotations needs a longer key window — a decision someone makes on purpose and the audit record keeps, not a default we choose for you.
SPEC-04
A dial, not a switch
Choose precision per field: exact age or a five-year band, street or region, full date or just the year. Trade detail for protection, field by field.
Precision is set per field rather than per dataset, because a dataset rarely needs the same fidelity everywhere. Exact age or a five-year band. Street, town or region. Full date or the year alone. Each setting is a trade between the detail the work needs and the exposure it carries, and each one is written into a tamper-evident audit record with who made it and when.
What stays your decision
A dial turned far enough down will break analysis that needed the detail. It exists so that trade is made deliberately, by a named person, on a record — not so it quietly disappears.
SPEC-05
Your perimeter, your rules
Self-hosted engine deployments run inside your environment. Hosted products have different data flows.
A library, sidecar or container lets your own system call the engine locally. In that deployment, the original values do not need to reach the Synthaveil hosted API. Keep key management, access controls and updates in your operating plan.
What stays your decision
This statement covers the self-hosted engine. Check the product and mode before applying it to a browser extension, hosted API or portal.
SPEC-06
Clean provenance
Stand-ins are built from official public statistics. Nothing scraped, nothing bought, nothing leaked.
Where the material behind a stand-in came from is a question worth asking of anyone selling this. Ours is official public statistics, with its sources documented. Nothing scraped, nothing bought from a broker, nothing leaked.
What stays your decision
Official statistics describe the populations they measure. For a population they do not cover, we agree the approach with you before any data goes through.
You hold the key, so your data remains personal data in your hands. The AI tool or vendor receives stand-ins with no key or mapping to link them back. All example data on this site is illustrative.