NI Number Encryption to Ensure Accurate Profile Identification

Why the NI Number Field Was Introduced for Accurate Profile Identification

The National Insurance (NI) number field was introduced at the request of NHS Trust clients who required a reliable method to prevent duplicate Profiles and accurately match data with internal HR and learning systems. Names, email addresses and other fields can change; NI numbers do not. If an individual attempts to create a second Profile using the same NI number, the system blocks it immediately, ensuring consistently high‑quality workforce data.

Many NHS Trusts require staff to complete mandatory and other essential training before their first day of employment. However, many new starters will not yet have an ESR number because the Trust’s internal HR processes— which vary between organisations—may not have been completed in time for induction. In addition, large cohorts such as military personnel, outsourced staff, university students, and volunteers are not on ESR at all and therefore do not have an ESR number.

To help illustrate these onboarding and data‑matching challenges, you can view this animated explainer video. It demonstrates the timelag issues inherent in ESR and shows how CATQR captures every attendee in real time.

The Profile ID is the unique identifier for an individual’s Profile Account. Only a pseudonymised, encrypted version of the optional NI number is ever stored in the system. This design ensures long‑term data integrity: names, email addresses and other fields can change over time, creating duplicate records, fragmented histories and undermining the validity of portable evidence required under the GDPR Right to Data Portability.

GDPR-Compliant NI Number Pseudonymisation (Encryption)

The NI number field is protected using our advanced encryption algorithm, and critically, the raw NI number is never stored in the database. Access to the separate decryption tool is strictly limited to an authorised NHS Trust administrator—typically a data analyst—who must authenticate using Multi‑Factor Authentication. This controlled access allows the Trust to decrypt NI numbers only when necessary to reconcile Profile records with internal HR or Learning Management Systems.

If an individual attempts to create a second Profile using the same NI number, the system blocks it immediately, preventing duplicates and maintaining consistently high‑quality data. The NI number field is protected using our advanced encryption algorithm, and the raw NI number is never written to the database. The resulting 15‑character Profile ID is derived from billions of possible combinations, providing a highly robust, collision‑resistant identifier.

When individuals enter made‑up NI numbers, the risk of duplicate Profiles and fragmented attendance records increases, particularly when staff move between NHS organisations. If an individual chooses not to use their real NI number, they must create a unique number using the NI number format (2 letters, 6 numbers, and 1 letter) that has never been used before. With billions of possible combinations, the risk of collision is low but not zero.

To support clarity at registration, the on‑screen instructions state:

Profile Data Fields Stored (Personal, Non-Personal and System-Generated)

All data fields stored in the system for an individual’s Profile.

1. First name
2. Last name
3. Student number (Optional)
4. Position title
5. Department
6. Employee number (Optional)
7. Organisation
8. E-mail address
9. Profile ID (system generated from the encrypted NI number)

In addition to the Profile fields listed above, further data is captured at the point of attendance. When an individual scans the CAT Class QR Code, the system records the Class, the Attendance Date & Time, and links these directly to the individual’s Profile ID. Separately, the organiser (such as an administrator or trainer) may optionally record the Competency outcome for that session, for example a pass or fail and any notes. This ensures that class‑delivery, attendance and competency data are consistently aligned to the correct individual, supporting accurate compliance reporting across NHS organisations.

Individuals can be assured that their data is stored securely within Microsoft UK data centres. We hold all relevant cyber‑security accreditations, including Cyber Essentials Plus as mandated by the National Cyber Security Centre (NCSC). We have had zero data breaches and are registered with the UK Information Commissioner’s Office. For all processing activities, we act solely as the Data Processor, with each NHS Trust serving as the Data Controller for the information it provides and manages.