How to Send and Receive Encrypted Gmail Messages

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Today it is commonly understood that free online services are not really free. Service providers get to monetize the information they gather about their users. This way, for better or worse, they are able to customize their users’ online experience.

There are many reasons, however, for being able not to disclose all your content, all your information to these service providers.

Let’s say, for example, that you have a business idea and you want to share it with your business partner. Let’s say that you both use Gmail for your email needs. But this message is so important that you want to make sure nobody else can read it except for your business partner.

Gmail doesn’t offer a simple encryption method. But there’s Mailvelope — a nifty browser add-on that does.

Incidentally, it can be used not only with Gmail, but also with many other free email providers, such as Yahoo, Outlook, or GMX.

Setting It Up

Setting up Mailvelope is super easy.

Install it as an add-on into Mozilla Firefox or as an extension into Google Chrome. The installation doesn’t even require a browser restart.

How Does It Work

Mailvelope utilizes public-key encryption. It is an asymmetric way of message encryption. This simply means that the sender and the receiver don’t share the same secret key to encrypt and decrypt the message.

Each user generates his or her own key-pair consisting of two parts — a public key which is shared with all message receivers and a private key which is never shared.

Public keys are used to encrypt outgoing messages. The private key is used to decrypt incoming messages. It is a very elegant and efficient method of sending messages safely.

The beauty of the method is that it is very easy to create a key-pair but it is mathematically impossible to re-create the private part of the key-pair from its publicly available part.

Creating a Key-Pair

To generate your key-pair, click on the Mailvelope icon in your browser next to the ≡ hamburger icon.

Select Options from the drop-down menu.

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Mailvelope — Icon Options

Now you arrive at Mailvelope’s Options page within your browser.

Click on the Generate Key tab in the left pane of the Options page.

Fill out your name and your email address in the right pane. Your email address must be the one you will be actually using to send out encrypted messages.

mailvelope-key-generator

Mailvelope — Key Generator

Then enter and re-enter a strong password.

If you don’t know how to create a strong password, read my previous post regarding this topic.

Remember to store this password safely. You will need it in the future.

Finally click on the Submit button.

After a few seconds, Mailvelope will have successfully generated your key-pair and added it to your key ring.

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Mailvelope — Primary Key

Now click on the General tab in the left pane of the window.

In the right pane, select your Primary Private Key — the key you just generated.

And tick the box next to Always add primary key to list of recipients.

This setting is important because it makes sure that your key will be added to all outgoing emails, so that you will be able to decrypt your sent emails, too.

Exporting and Importing Public Keys

To make proper use of asymmetric encryption, senders and recipients need to exchange their public keys.

Exporting

You need to send your public key to your recipients, and they need to send their public keys to you. You use the public key of your recipient(s) to encrypt your outgoing messages. Obviously, you also need to add your own public key to these messages, otherwise you won’t be able to decrypt the messages you send out.

To be able to share your public key, you need to export it from your key ring. Click on the Display Keys tab in the left pane of Mailvelope’s Options page.

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Mailvelope — Export Public Key

In the right pane of the window, select your name and then click Export > Display public key.

In the Export Key pop-up window click on the Create file button. You have now created an .asc file on your hard drive with your public key.

Share this file with your email recipients. They will have to import your public key into their key rings.

Importing

To import your recipients’ public keys into your key ring, click on the Import Keys tab in the left pane of Mailvelope’s Options page.

mailvelope-import-keys

Mailvelope — Import Keys

In the right pane, add the public key file by clicking on the Browse… button. Locate the key file on your hard drive, open it and click Submit.

After successfully importing the public keys, they are added to your key ring and you are ready to send encrypted messages to these recipients.

Encrypting Messages

mailvelope-in-gmail

Mailvelope in Gmail

To do so, compose a message.

When done, click on the icon hovering in the message body window.

In the pop-up click on the yellow lock icon located in the upper-right corner of the window.

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Mailvelope — Encrypt Message

Then add all the people you want to be able to decrypt your message by selecting them from the list of available keys and clicking on the green Add button.

Again, don’t forget to add your own email address.

When you are done, click OK and then Send.

Important Note

Currently, you can only encrypt plain-text messages and you cannot encrypt attachments with Mailvelope.

Decrypting Messages

Let’s say that you receive an encrypted message. The sender of the message already encrypted it using your public key. To decrypt the message, all you need is your own private key — the secret part of your key-pair that you have never shared with anyone.

mailvelope-decrypt-message

Mailvelope — Decrypt Message

To decrypt a message, click on it. It won’t be readable at first but then an envelope icon with a smaller yellow lock icon in front of it will appear.

By clicking on the envelope you bring up the Key unlock pop-up window.

In this window, you have to enter the password to your private key — the password you created earlier when you generated your key.

Then click OK.

Now you can read your decrypted message.

Final Thoughts

I hope that this post will encourage you to use email encryption as much as possible. With Mailvelope, setting up your key-pair and starting to send out encrypted messages takes only a few minutes. And you can use it with any free email service provider.

But the greatest benefit is that your online life, as far as your email communication is concerned, will cease to be a product ready to be monetized by someone else.

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