Pseudonymisation is a data processing technique that preserves consumer privacy by obscuring personally identifiable information. While anonymising processes do this by removing the relevant attribute values (or identifiers) from fields such as name, address, or phone number, pseudonymisation replaces the relevant attribute value with stand-in or alias values, or pseudonyms.
Why would someone use pseudonymisation?
Pseudonymisation is a technique intended to preserve privacy and data confidentiality. It is a global practice, noted in both the GDPR and CCPA data regulatory standards. For example, Recital 29 of the GDPR states that the GDPR aims “to create incentives to apply pseudonymisation when processing personal data.”
Pseudonymisation’s advantage over strict anonymisation techniques is twofold: 1) pseudonymisation preserves the ability for a data owner to securely reidentify an individual data record under specific managed circumstances, such as when it’s required for regulatory reporting or notification, and 2) the creation of consistent pseudonyms over related records enables those records to be linked, preserving the ability of data to be augmented or enriched.
Think of the data owner as a chef with countless recipes in her head and dishes that she alone can make. If we consider her culinary repertoire as data, pseudonymisation allows her to strip out secret ingredients but still logically group her entrees, desserts, and appetisers together and enhance them with new flavours. Strict anonymisation would only allow the former.
When would data collaborators choose to use pseudonymisation?
Beyond preserving consumer privacy, pseudonymisation is also a technique enabling marketers to securely collaborate for analytic and measurement purposes at both the aggregate and data record level. For example, pseudonymised records can still be linked across multiple partner data tables to produce insights about a path to purchase or the true incremental impact of a campaign. Pseudonymised records can also be used to create rich audience behavioural models to guide marketing planning and tactics.