How to Encrypt Emails on Thunderbird

If you’re drawn to Thunderbird as an email client, there’s a good chance that you’re more security-conscious than the average internet user. The majority of email users across the web aren’t going to get excited about a free, open source, cross-platform email client that stays true to the tenets of the Mozilla Manifesto—but for those who do, Thunderbird presents an attractive alternative to some of the more well-known email clients on the market. That said, it doesn’t offer encryption protection for your emails right out of the box.

If you were reading this post a few months ago, we could have told you that the fix for that was simple: just use Enigmail. But Thunderbird announced recently that they would be ending support for the encryption solution that previously enabled users to utilize OpenPGP encryption to protect their messages—meaning that users who have been relying on Enigmail will have to find a new way to keep their emails safe, while new Thunderbird users will have to look elsewhere for this functionality.

Luckily, new alternatives are on the horizon: in addition to a new add-on from Mozilla that will replace the Enigmail functionality, there’s also p≡p for Thunderbird. We may be a little biased, but we think that the latter option is going to be the easiest solution for most users—and we’ll demonstrate why below.

Enigmail’s Gone: Now What?

Though Enigmail’s functionality was crucial for security-minded users, it didn’t necessarily provide the world’s most seamless user experience—in addition to downloading Enigmail itself, users who wanted encrypted email had to download additional third party software like GnuPG or GPG4Win, then power through the actual OpenPGP setup process within Thunderbird. In this sense, it’s not too shocking that Mozilla ultimately opted to pivot away from it.

And, of course, after manually configuring the rules for sending and receiving public keys, then generating the actual public and private keys, the encryption itself involved even more manual effort on a per-email basis: If you were typing an email to a new contact, you had to remember to add your public key from the OpenPGP dropdown menu before sending—then, when the contact responding, you had to manually import their public key so that an encrypted email exchange could begin. User also had to use their own encryption key to manually sign the messages in order to ensure their integrity (i.e. that the message that reached the other endpoint hasn’t been altered or tampered with in any way).

Even the kinds of users who are drawn to Thunderbird could be forgiven for finding this all a little bit daunting. And with the rise of alternative methods of securing messages on this platform, there’s an opportunity even for those who previously relied on Enigmail to get improved functionality—and thus more consistent protection. 

How to Install p≡p for Thunderbird

Now, none of that is meant as a critique of Enigmail—to the contrary! We at p≡p were big fans of the add-on. In fact, Enigmail 2.0 and 2.1 (aka “Enigmail/p≡p”) contained a p≡p “Junior Mode,” meaning that they used the p≡p engine for their cryptography. We’ve worked with the folks at Enigmail for years to provide a seamless encryption management experience, and now we’re working to continue that mission and offer users the privacy and protection that they’re used to. More than that, we’re working to make that level of privacy easier than ever by automating every element of the encryption process.

So, how do you take advantage of these automated encryption workflows? Just download p≡p for Thunderbird: p≡p offers free and open source email encryption for Thunderbird users that’s compatible with OpenPGP deployments that other users in your contact list might be relying on.

Like we said above, from our perspective this is now the easiest way to encrypt your emails on Thunderbird. Why do we believe that? Two reasons: incredibly straightforward installation, and automated encryption functionality. To wit, installation occurs in just a few easy steps:

  1. Install Thunderbird for your platform first if you do not have it installed yet. Find the download on the Thunderbird website:
  2. Visit https://www.p≡ and click the installation button that matches your operating system. Then, run the installation file by double clicking or pressing Enter after the file is selected.
  3. The first p≡p for Thunderbird installation screen will appear. While loading, the installer checks for system compatibility and verifies that you have a supported version of Thunderbird installed.
  4. The p≡p for Thunderbird licensing agreement will appear. Please read through this agreement in its entirety. After you have read and agreed to the terms and conditions of the licensing agreement, please check the “I accept the terms in the License Agreement” checkbox and click Install.
  5. The installer may need your permission to continue. When the below dialog appears, type your password (if required) and click Yes.
  6. p≡p for Thunderbird will now be installed. During installation the progress bar may pause momentarily before it finishes.

It’s as simple as that. In the next section, we’ll get into what happens once the installation is complete—i.e. how p≡p automatically protects your emails in transit on Thunderbird.

How p≡p Automates Email Encryption on Thunderbird

Following the installation process, p≡p automatically generates encryption keys on an ongoing basis, and uses them to protect your emails without you having to lift a finger. Likewise, it automatically takes in key material from messages you receive in order to establish secure and trusted connections. Unlike Enigmail, it’s truly a plug-and-play encryption solution.

This stands in contrast to even the most user-friendly deployments of OpenPGP. Though p≡p is using PGP encryption standards, and is compatible with PGP, it automates all of the manual effort, such that users can reap all of the benefits without any of the fuss. Our system encrypts opportunistically based on a trust-on-first-use (TOFU) model, which means that any time p≡p receives something that can be used as key material based on our cryptography standards, we automatically import it and use that to establish trust with a particular system (e.g. the sender of the email). This ensures that all of the messages that appear to be coming from that channel really are. From there, you can perform an offline Trustword exchange to make absolutely sure that you’re talking to who you think you are. Then, even as keys reach their expiration dates and are swapped out, you can continue to communicate with the certainty that no one is listening in on your conversation, and no one is impersonating your contact in order to steal your information.

All this might sound a bit technical, but from a user perspective the only big change from normal Thunderbird activity is that p≡p provides color-coded indicator lights to let you know the encryption status of each conversation:

  • No color – Not secure: you haven’t been able to exchange key material with this system or email communication partner yet, so the channel isn’t secure.
  • Yellow – Secure: once you’ve (automatically) exchanged key material, a secure connection is established—which means that all future communications on this channel will be encrypted and signed to ensure confidentiality and integrity.
  • Green – Secure and Trusted: once your connection is secure, you can exchange Trustwords offline to ensure you’re talking to who you think you are. This is as simple as reading out 5-10 automatically-generated words in your chosen language to make sure they match what’s on your communication partner’s screen. Once this has been accomplished, you can ensure not just confidentiality and integrity, but authenticity (i.e. the message is from whom it claims to be from) as well.
  • Red – Mistrusted: This means that the message didn’t contain the expected key material, and is therefore likely to be spam or an attacker. If you see this indicator light, you know to proceed with extreme caution.

Again, the TOFU model means that the progression from the first, unencrypted message to the secure yellow traffic light being activated all occurs in the background. Then, it’s the work of a minute or two to change the traffic light from yellow to green.

In this way, you’re able to get all of the protections that Enigmail offered—all without the clunky manual effort. Mind you, this isn’t just a matter of convenience. To the contrary: the harder an application or add-on is to install and use, the more likely you are to see misconfigurations and user errors eroding the foundations of peoples’ message protections. Simply put, if you weren’t using Enigmail perfectly, you weren’t getting the protections you wanted. By automating the entire process from end-to-end, p≡p does away with that risk for Thunderbird users, resulting in more robust protection all around.

How to Install p≡p Across Devices

One of the other benefits of the p≡p system is that users are able to utilize p≡p’s Sync protocol to extend their encryption protections across devices—i.e. a user who has Thunderbird installed on two different devices could connect those devices to maintain a coherent identity from an encryption standpoint.

To make this happen, the p≡p sync protocol automatically creates a device key on Device #1 (let’s say your personal laptop); it then sends discovery messages to its own accounts (i.e. the email accounts you use with Thunderbird), and all other devices that are logged into that account automatically initiate a device group dialog. From there, keys are exchanged and Trustwords are checked—just like you would do with a new communication partner—resulting in the creation of a device group with a cohesive identity and shared keys.

In this way, Thunderbird users are empowered to do more than just protect their messages in a patchwork of device-specific channels—they can actually maintain security seamlessly across multiple devices. This makes communicating with others much easier, and it doesn’t require you to compromise message protection at all. In fact, it should increase your security, since it reduces the chances that you accidentally send a message from an unsecured device. If you’re using Thunderbird, there’s every chance that you’re conscientious about your privacy—and p≡p helps cement that privacy no matter what devices you use for email.  

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