Data in use refers to digital information that is actively being processed by a computer system. Unlike data at rest (stored data) or data in transit (data being transmitted), data in use is currently being accessed, modified, or generated by applications and users. This includes information temporarily held in system memory (RAM) or CPU registers during computation. Protecting data in use is crucial, as it is vulnerable to threats like memory scraping, unauthorized access, or exploitation of software vulnerabilities. Security measures such as encryption-in-use and secure enclaves are often employed to safeguard sensitive data while it is being processed.