In the Posteo webmail interface, you can use genuine end-to-end encryption with the browser add-on Mailvelope.

In this help article, we show you how to use Mailvelope to send encrypted emails and how to make encrypted emails readable.

Contents

• How to send an end-to-end encrypted email
• How to make an end-to-end encrypted email readable

Requirements

1. You have installed Mailvelope in the browser
2. You possess a key pair for your Posteo email address

How to send an end-to-end encrypted email

In the webmail interface, click Compose and encrypt and then proceed as follows:

1. Enter the recipient
2. Import the recipient’s public key, if required
3. Enter a Subject
4. Compose your message
5. Attach an attachment to your email via add attachment, if required
6. Click Encrypt and send, to send the email
   

As soon as you click Encrypt and send, Mailvelope encrypts the content of your email – locally in your browser. The message is transferred encrypted to the Posteo server.

How to import your public key in Mailvelope

If you have not yet saved a recipient’s public key in Mailvelope, Mailvelope will advise you of this before sending. In many cases, the Posteo key directory will automatically find the required key. Import then consists of two steps:

1. Below the address line, click the Import link
2. Click Confirm

Sometimes, the Posteo key directory does not find your public key. In this case, ask the recipient to send your their public key as an email attachment. The file can then be imported directly to Mailvelope.

How to make an end-to-end encrypted email readable

You can make an end-to-end encrypted email readable by opening the email in the Posteo webmail interface. Mailvelope automatically recognises encrypted emails and helps you with decryption:

1. Open an encrypted email as you would any other email in the Posteo webmail interface
2. Enter your key password
   The key password was set during installation of Mailvelope.
3. Confirm your entry by clicking OK
   Tip: Place a tick next to Remember password temporarily. Mailvelope then saves your key password for 30 minutes. You will then not need to enter your password again straight away if you wish to read multiple encrypted emails after one another.

Tips

• Saving drafts is not possible in Compose and encrypt mode.
• Mailvelope decrypts your emails locally on your computer. The emails remain encrypted on the Posteo servers at all times.

Related help articles

• Can I export my OpenPGP key from Mailvelope?
• How do I install end-to-end encryption for Posteo with Mailvelope (PGP) in the browser?
• Wie hinterlege ich meinen öffentlichen Schlüssel im Posteo-Schlüsselverzeichnis?
  
• How do I activate inbound encryption with my public PGP key?