How to encrypt eMail?

There are different ways to send an encrypted email and this article shall cover the major aspects and methods and give you a quick overview, how to do it.

Methods of encryption

No other service than “email” is so diversified in usage around the web! You can read and write email in your browser, with Outlook on Windows, with Outlook on your Smartphone, with other Smartphone clients – naturally different ones on Android and iOS – Thunderbird on Windows or Linux, etc. – the list goes on and you get the picture.

So, let me clean that up and take about the basic concepts of encryption – because there are 2:

  1. Symmetric encryption: you know that as “enter your password”
  2. Asymmetric encryption: you know that probably as PGP if it comes to eMail

While “symmetric” is easy to understand, the asymmetric needs another inch of your brain:

With asymmetric methods, you need a public key and a private key. I would need to send you my public key before we start talking. Then you would encrypt my mails to me with my PUBLIC key and I can unlock your emails with the PRIVATE one, that matches the public one I have sent you before.

That is one of the reasons, these asymmetric versions never took off, really: you would probably not have the key on your smartphone or the other device you just used to receive the email.

So, I am personally promoting the symmetric form of encryption, which ought to be enough as long as you have the password for the eMail I will send you!

Places of encryption

Take a look at the way your eMail takes through the Internet, starting on the left in your eMail client.

sending emails online

The little lock shall indicate, where you should implement email encryption and that is in your client (like Outlook, Thunderbird or your Smartphone clients). Everything else is out of your control and therefore not considered safe. There are methods to make the “way of the data” from your outbox to the receivers inbox secure, too. But ultimately is the best security the one you control!

There are providers like Protonmail or Runbox (which we use!) that help you in different ways to implement an encrypted way from your client to the rest of the world, but frankly: adding a layer of security over the offer of others might be a good idea, because in order to guarantee security, you have to be sure, what happens from the moment on the email leaves your realm.

Tools of encryption

There are a lot – and I mean really A LOT of tools for private data exchange out in the wild. Some tools follow the idea to put encrypted files in the cloud and let you exchange the really private documents via cloud services.

Besides our own Outlook Plugin, there is the more complicated, but free PGP Encryption that you can use for a secure exchange!

My favourite ones beyond pure eMail communications are:

  • Boxcryptor (they work on top of the usual cloud providers like Dropbox,, OneDrive, etc.)
  • (a Canadian encrypted cloud provider)
  • 7zip for Windows (like all better Archiving Tools, you can set a password for the compressed file, cool!)

and for pure eMail exchanges, we are using with our own Outlook Plugin as already mentioned!

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