Which preventive measure can protect sensitive data while it is actively processed on a system?

Data encryption is a crucial preventive measure for protecting sensitive data while it is actively processed on a system. Encryption scrambles the data in such a way that only authorized users with the correct decryption keys can access it in a readable format. This means that even if an unauthorized individual gains access to the system where the data is being processed, they would not be able to interpret or use the sensitive information without the necessary decryption key.

This safeguarding is particularly important during data processing, as data can be vulnerable to exposure through various means such as system vulnerabilities or insider threats. By employing encryption, organizations can ensure that sensitive information remains confidential, thus adhering to privacy regulations and maintaining trust with users.

Other options like data segregation, data archiving, and access control, while important security practices, do not directly provide the same level of protection for data actively being processed. Data segregation focuses on keeping different types of data separate to minimize risks, data archiving involves moving data to storage where it is not actively used, and access control is more about who can view or use data rather than securing the data against unauthorized access during processing.