DEFINITION
Data Masking
Replacing sensitive values with realistic-looking substitutes so the data remains usable while the originals never leave the device.
In depth
Data masking transforms sensitive fields — names, account numbers, identifiers — into substitutes that preserve format and meaning but no longer expose the underlying information. A masked credit card number still looks like a credit card number to a downstream system, but it is no longer linkable to the real cardholder. Masking can be reversible (the original can be recovered with a key) or irreversible (the original is discarded). It is distinct from encryption, which produces unreadable ciphertext, and from redaction, which removes the value entirely.
Examples
- Replacing "Acme Corp v. Smith" with "Client A v. Witness 1" before sending a draft brief to an AI model.
- Substituting a real Social Security Number with a structurally valid synthetic one for a test database.
- Swapping a patient name for a stable pseudonym so a clinician can still ask follow-up questions about the same record.
How Locke handles data masking
Locke masks sensitive data locally, before any text leaves your device. Locke 1.0 replaces detected values with one-way placeholders, so the AI never sees raw values. Reversible tokenization is planned shortly after 1.0.
See the productRelated terms
- Tokenization
Replacing a sensitive value with a non-sensitive token that maps back to the original through a separate, controlled lookup.
- Redaction
Removing or blacking-out sensitive content so it is no longer present in the document or prompt.
- Personally Identifiable Information (PII)
Any information that can identify a specific person, either directly (name, SSN) or in combination with other data (zip code + birthdate).
