Which of the following methods is frequently used to protect sensitive data?

Data encryption is a widely utilized method for protecting sensitive data because it transforms readable data into an unreadable format, ensuring that only authorized users with the correct decryption key can access the information. This process significantly enhances the security of data both in transit and at rest, safeguarding it from unauthorized access, theft, or interception.

In the context of protecting sensitive information, encryption plays a critical role in various applications. For example, when sensitive data is transmitted over networks, encryption protocols, such as TLS (Transport Layer Security), can be employed to secure the data against interception by attackers. Additionally, when sensitive data is stored on devices or in databases, encryption protects it from unauthorized access, even if an adversary gains physical access to the storage medium.

Other methods mentioned, while valuable in their own right, do not provide the same direct mechanism for transforming data into an unreadable format. Network segmentation helps limit access to sensitive information by dividing networks into segments, but does not protect the data itself. Access control lists enforce user permissions on who can access specific data, while firewall rules protect networks by controlling traffic but do not encrypt the data itself.