Encryption is the practice of making data, such as a message, harder (and hopefully impossible) to read by unintended recipients. Encryption is talked about in two ways: data at rest (stored, for instance, on a hard drive or USB key) and data in transit (data as it’s sent over the local network or the Internet).
By default, emails are not encrypted. The contents of any email are visible to your email service provider, your recipients’ provider and anyone who is able to intercept it along the way. You should treat email like a digital postcard, anyone who happens to handle it can read it. Even if your provider uses encryption for communicating between your service and the receiver’s service, it’s likely that each will store that message in plain text at both ends.
Encrypting your communications will prevent anyone that accesses from reading it. If a hacker intercepts your encrypted message while it’s being sent, or accesses it while it’s being stored, it will be unintelligible.
You can use methods such as PGP encryption to secure your own emails, but you need to collect the public key of everyone you want to send secure email to, then encrypt each message. We suggest a modern, end-to-end encrypted messaging service for most people, as an easier choice.
End-to-end encryption means that every message sent between two or more people is encrypted on the sender’s device before the message goes out to the Internet and can only be decrypted by the specified recipients. This means that the 3rd party service which created and manages the app can not view the message, because only the sender and the receiver have the digital keys to unscramble it. When you send messages via an end-to-end encrypted app, you are protecting that information from being read or modified by others, even if they intercept it or hack the servers it’s stored on. Apps that use end-to-end encryption make the process completely transparent — you don’t have to take any extra steps. These apps are generally free or low-cost.
When using an end-to-end encryption to communicate, it’s important to keep the device you are communicating with secure. For help with basic security on Windows and Mac computers, see our guide, 5 Ways to Increase Security on your Windows or Mac Computer.
If you’re using a smartphone to communicate, ensure that you have the screen lock set up with a complex passcode, the “find my phone” service set up, and that you are installing any updates you receive. Learn about apps for encryption in our next guide!