What is email encryption and how does is work

If you don’t encrypt your emails, you’re sending them via an easily attackable connection and also in plain text! This not only makes it easy for unauthorised persons to intercept emails on their way to the recipient, but also allows them to easily read the messages once they’ve intercepted them. You also expose yourself to the latter risk if you store received messages in the archive folder or mailbox of your account without encrypting them. Since the 25^th of May, 2018, the GDPR (General Data Protection Regulation) has been in force throughout Europe, and therefore you should no longer take the issue of email encryption lightly and protect your messages adequately against unauthorised access.

Without encryption, the contents of emails are about as secret as the contents of a postcard: if the card or email falls into the wrong hands, the entire text can be read easily. For this reason, powerful encryption methods have been developed to either generate an encrypted email or encrypt the email transfer. There are three categories when it comes to the encrypting emails:

1. Encrypting the email transfer
2. Encrypting the content of emails
3. Encrypting saved emails
    

Sending encrypted emails - with SSL/TLS

The Transport Layer Security (TLS) transmission protocol is a necessary tool for securely transferring email content. However, it is better known under its former name Secure Sockets Layer (SSL). An email with SSL or TLS encryption cannot have its content deciphered by third parties during the data exchange because they do not have the key that’s necessary for decryption. It does not matter whether the electronic mail is retrieved or sent via an email client such as Outlook or via a web browser. SSL/TLS technology is not only used for sending e-mails, but also for online banking and e-commerce.

Encrypted emails with S/MIME or PGP

If you want to encrypt the actual content of emails, you can choose between different techniques - such as the standard method S/MIME or PGP, both of which use asymmetric encryption. While traditional coding and decoding methods access the same key, asymmetric encryption uses two keys - a private one known only to the sender and a public one freely accessible to all recipients.

Encrypt archived emails with system tools or third-party tools

Encrypting electronic messages is of utmost importance even if they remain stored in your inbox or are archived after being read. By encrypting them, you can prepare yourself in case criminals gain access to your account and therefore to all your existing emails. The above-mentioned encryption methods make it very difficult (or even impossible) for hackers to read your data. For additional data protection, use two-factor authentication (especially when using email web clients) or encrypt your hard drive or relevant folders and files (when using email desktop clients or apps).

Encrypting email transfer to desktop clients such as Outlook

You can also encrypt the connections to mail servers via SSL/TLS in the mail client on your PC or in a corresponding app on your smartphone or tablet. The decisive factor is which port is being used for sending and receiving. The corresponding settings can be found in the account settings of the mail program. There is also often a general option to enable email SSL/TLS encryption. As soon as this is switched on, the program will usually set the appropriate ports automatically. Otherwise, you can do this manually, entering different numbers depending on the input server type (POP3 or IMAP):

In both cases, select “SSL” as the connection type. For the outgoing server (SMTP), enter the following port (connection type: automatic):

Many users are unaware of the danger posed by poorly secured email traffic. They involuntarily invite third parties to read their messages. Nearly all popular email programs and services support encryption features that allow you to send and receive encrypted emails and generally secure their transfer. Because these features are set up with relatively little effort, you should not hesitate to encrypt your emails and enable existing SSL options for secure transfer.