Drive encryption is a form of data-at-rest encryption that encrypts the entire hard drive or solid state drive. This means that all the data on the drive, including the operating system, applications, and files, are protected from unauthorized access. Drive encryption is usually implemented at the hardware or firmware level, and requires a password, PIN, or biometric authentication to unlock the drive. Drive encryption is the most comprehensive and secure way to achieve data-at-rest encryption, as it prevents anyone from accessing the data without the proper credentials, even if they physically remove the drive from the server.