What is the purpose of a product key?

A product key serves as a unique identifier and license to validate a user's right to install and use specific software. It ensures that the user has legitimately acquired the software and helps prevent piracy. When a user attempts to install a program, entering the product key confirms that they are authorized to use that version of the software, often unlocking its full features.

This authorization mechanism is essential for software publishers, as it allows them to control the distribution and use of their products. The product key may also help track how many copies of the software are in use, which is important for licensing agreements.

The other options focus on different functionalities: installing updates generally involves processes that do not require a product key; activating security features pertains to different types of software protections; and validating hardware compatibility is a function often handled by system checks or external software rather than through a product key.