With device encryption the contents of your device’s storage–the part that contains the operating system, programs you have installed, and your personal data–are scrambled so that it cannot be accessed when the device is off or when you are logged out.
Without device encryption enabled, whenever someone steals your device, finds your lost device, or otherwise accesses your hardware they can easily read your files, gain access to your online accounts, and impersonate you. Even worse, an attacker can install malware that allows them to remotely access all your activities.
Although full disk encryption is enabled by default on some mobile devices, it must be manually set up on all laptop and desktop computers, and many phones and tablets.
- Windows: Security Planner / Windows Encryption
- IMPORTANT: By default, Microsoft makes a cloud-based backup of your device encryption key. This means that Microsoft, and any government it cooperates with, is able to easily decrypt your device. If you are concerned about the possibility of a national government gaining access to the contents of your device, you should disable this “feature” and generate new encryption keys now.
- macOS: Security Planner / Mac Encryption
- Linux: Nearly any Linux distribution will allow you to enable device encryption when installing the OS. There are two different types:
- “Full Disk” Encryption: This approach encrypts everything on the device’s primary storage, including the operating system. You will be prompted for a separate password when the device powers on.
- “Home Directory” Encryption: This approach does not encrypt the operating system. It will protect your personal data, but makes it easier for an attacker with access to your device to install malware.
Limitations Device encryption does not always work! If your password is not complex, then a computer can easily guess it and unlock your device. Also, device encryption provides no protection against viruses and malware. If your data is copied to a cloud-based backup service and this service becomes compromised or cooperates with the government, then device encryption will not protect your data (unless using a service which specifically supports “client-side” encryption).
Authentication Must Be Enabled Device encryption is not effective unless the device requires authentication to use. For example, you are required to log in when using your laptop or provide a PIN when using your mobile device.
Makes Disk Recovery Impossible Full disk encryption can also increase the risk of you losing access to some of your information if robust password- or PIN-management practices are not in place. A lost password or PIN, as well as failure of the part of the disk where the encryption keys are stored, will generally mean you (as well as anyone else) cannot recover your data. Ensure that you keep periodic backups of your data to minimize the risk of data loss.
Device Must Be Off or Locked Device encryption provides protection only when your computer is turned off, or turned on but awaiting a password to start up. Once you have logged in, the computer has the secret key needed for decrypting your data in its memory and so even with the screen locked there is some risk of someone obtaining access to the contents of your computer while it is running (or even sleeping). However, in general, surmounting those controls is a highly technical attack and that risk shouldn’t stop you from keeping your computer turned on or logged in when you need to work. It is, however, best to to turn off your devices whenever your device will be away from you in a hostile environment. If you are concerned you may be a target of an attack, then it is best practice to keep your device physically in your presence at all times.