How to encypt your emails with SSL/TLS

Sending emails without en­crypt­ing them means trans­mit­ting them over a vul­ner­a­ble con­nec­tion and in plain text. This allows unau­tho­rized in­di­vid­u­als to easily intercept and read these messages. With SSL/TLS, you can encrypt your emails and protect them from unau­tho­rized access.

How to secure emails with en­cryp­tion

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

1. Encrypt the trans­mis­sion of emails
2. Encrypt the content of emails
3. Encrypt stored emails

How to send encrypted emails with SSL/TLS

The essential tool for securely sending email content is the uni­ver­sal­ly ap­plic­a­ble trans­mis­sion protocol Transport Layer Security (TLS). It is better known by its former name Secure Sockets Layer (SSL). An email with SSL/TLS en­cryp­tion is char­ac­ter­ized by its content being in­de­ci­pher­able to outsiders during data exchange, as they do not possess the required key for de­cryp­tion. It does not matter whether the email is accessed or sent via an email client like Outlook or through a web browser. SSL/TLS tech­nol­o­gy is used not only in email trans­mis­sion but also, for example, in online banking or e-commerce.

Secure email for digital privacy

• Pro­fes­sion­al data and security pro­tec­tion
• Secure encrypted email with SSL/TLS
• Email pro­tec­tion on any device thanks to firewalls and spam filters
• Daily backups, daily pro­tec­tion

See plans

Encrypted emails with S/MIME or PGP

If you want to encrypt the actual content of emails, you have various tech­niques available – like the standard method S/MIME or the well-es­tab­lished PGP, both of which use asym­met­ric en­cryp­tion. While tra­di­tion­al methods access the same key for coding and decoding, asym­met­ric en­cryp­tion involves two keys – a private key, known only to the sender, and a public key, freely ac­ces­si­ble to all re­cip­i­ents.

Encrypt saved emails using software

The en­cryp­tion of elec­tron­ic messages is crucial even when they remain stored in your inbox or archive after being read. Such en­cryp­tion ensures you are prepared in case criminals gain access to your account and thereby access to all existing emails. You can ensure ad­di­tion­al pro­tec­tion through two-factor au­then­ti­ca­tion (es­pe­cial­ly when using web email clients) or through en­crypt­ing your data or the relevant folders and files (when using desktop email clients or apps).

How to put email en­cryp­tion into practice

The most important building blocks for email en­cryp­tion and secure message trans­mis­sion have been briefly explained in the preceding sections. In the following sections, you will learn more about how to implement the in­di­vid­ual security measures.

Encrypt email trans­mis­sion in web clients

Reputable email providers have long offered their web services over the secure HTTPS protocol as standard. You can recognize this by the URL, which begins with “https” instead of “http.” Ad­di­tion­al­ly, in your browser’s address bar – typically indicated by a lock symbol – you can check if the webmail client has an SSL/TLS cer­tifi­cate.

En­crypt­ing email trans­mis­sion in desktop clients

Even in the mail client on your PC or in a cor­re­spond­ing app on your smart­phone or tablet, you can encrypt the con­nec­tions to the email server using SSL/TLS. The crucial element that needs to be defined for this is the port, used for sending or receiving. You can find the relevant settings in the account settings of the re­spec­tive mail program. There is often a general option to activate mail SSL/TLS en­cryp­tion. Once this is enabled, the program usually con­fig­ures the ap­pro­pri­ate ports au­to­mat­i­cal­ly. Otherwise, you can do this manually, where you will need to enter different numbers depending on the type of incoming server (POP3 or IMAP) and for the outgoing server:

• Incoming mail server (IMAP): 993
• Incoming mail server (POP3): 995
• Outgoing mail server (SMTP): 465

Select “SSL” as the con­nec­tion type. (Tech­ni­cal­ly “TLS” despite the “SSL” label.)

Encrypt email content (example: Mail­ve­lope)

If you want to send and receive encrypted emails as well as use a secure SSL/TLS con­nec­tion, you have numerous programs at your disposal with which you can access the S/MIME and PGP en­cryp­tion methods pre­vi­ous­ly mentioned. If you send and receive your email using a web client, the easiest way is to use a browser extension such as Mail­ve­lope, which will be used as an example in this article.

Mail­ve­lope is available for Firefox, Edge, and Google Chrome, allowing you to use PGP email en­cryp­tion in various webmail services. The first step is to install the extension through the plugin or extension center (direct links can be found on the Mail­ve­lope homepage).

When you launch the extension after in­stal­la­tion, a popup window will appear. Click on “Let’s start!” to start the con­fig­u­ra­tion. You will then be redi­rect­ed to the key man­age­ment, which at this point logically doesn’t contain a key pair for the planned email en­cryp­tion yet. To generate this, click on “Generate Key” and then enter the requested in­for­ma­tion:

Select the option “Upload Public Key to Mail­ve­lope Key Server,” allowing your contacts to obtain it from there to send you encrypted emails as well. Once the PGP key pair is generated, you will receive a success no­ti­fi­ca­tion and an initial encrypted email sent by Mail­ve­lope to the specified email address. Open the message, click the icon in the middle (“Show Message”), and then enter the password for the pre­vi­ous­ly created key:

The message will be decrypted, and a link will become visible. Click it to activate your email address and be able to encrypt emails in the future. For en­cryp­tion, you will now find a specific Mail­ve­lope button in the message editor of the re­spec­tive web client, which you must always use when you want to encrypt the content of emails:

Secure email for digital privacy

• Pro­fes­sion­al data and security pro­tec­tion
• Secure encrypted email with SSL/TLS
• Email pro­tec­tion on any device thanks to firewalls and spam filters
• Daily backups, daily pro­tec­tion

See plans

Email en­cryp­tion with IONOS Mail

IONOS email servers have per­ma­nent­ly disabled outdated TLS versions and SSL. If you’re using IONOS Webmail, there’s no need for concern—en­cryp­tion is au­to­mat­i­cal­ly and con­sis­tent­ly enforced.

When using IONOS Mail in an email program on your PC or cell phone (e.g., Outlook, Thun­der­bird, Apple Mail), make sure that SSL/TLS en­cryp­tion is enabled.

To enable SSL/TLS in your mail client, proceed as follows:

1. Open the mailbox settings.
2. Enable SSL/TLS en­cryp­tion for the mailbox.
3. Set the correct ports for incoming and outgoing mail servers:
   • Incoming via POP3 (SSL/TLS): 995
   • Incoming via IMAP (SSL/TLS): 993
   • Outgoing via SMTP (SSL/TLS): 465

How to enable en­cryp­tion for IONOS Mail on Android, iOS, and more can be found in the article on switching to SSL/TLS en­cryp­tion in the IONOS Help Center.