Referential Integrity

Referential integrity in the context of Philter is the process of replacing certain values with random but similar values while maintaining the same replacement value for the same original value. For example, the identified name of "John Smith" may be replaced with "David Jones", or an identified phone number of 123-555-9358 may be replaced by 842-436-2042. A VIN number will be replaced by a 17 character randomly selected VIN number that adheres to the standard for VIN numbers.

Referential integrity is useful in instances where you want to remove sensitive information from text without changing the meaning of the text and while maintaining the same replacement values for the same original values. This is enabled for each type of sensitive information in the policy by setting the filter strategy to RANDOM_REPLACE. (See Policies for more information.)

Referential Integrity

Referential integrity refers to the process of always anonymizing the same sensitive information with the same replacement values. For example, if the name "John Smith" is randomly replaced with "Pete Baker", all other occurrences of "John Smith" will also be replaced by "Pete Baker."

Referential integrity can be done on the document level or on the context level. When enabled on the document level, "John Smith" will only be replaced by "Pete Baker" in the same document. If "John Smith" occurs in a separate document it will be anonymized with a different random name. When enabled on the context level, "John Smith" will be replaced by "Pete Baker" whenever "John Smith" is found in all documents in the same context.

Enabling referential integrity on the context level requires a cache to store the sensitive information and the corresponding replacement values. Philter uses a Valkey cache to store these values. See Philter's Settings on how to configure the cache.

When Philter is deployed in a cluster, a Valkey cache is required to enable referential integrity across all nodes.

The referential integrity cache will contain PHI. It is important that you take the necessary precautions to secure the cache and all communication to and from the cache.