Email Self-Defense

Step 1.a Setup your email program with your email account

Open your email program and follow the wizard (step-by-step walkthrough) that sets it up with your email account. Look for the letters SSL, TLS, or STARTTLS to the right of the servers when you're setting up your account. If you don't see them, you will still be able to use encryption, but this means that the people running your email system are running behind the industry standard in protecting your security and privacy. We recommend that you send them a friendly email asking them to enable SSL, TLS, or STARTTLS for your email server.

Step 1.b Install the Enigmail plugin for your email program

In your email program's menu, select Add-ons (it may be in the Tools section). Make sure Extensions is selected on the left. Do you see Enigmail? If so, skip this step.

If not, search "Enigmail" with the search bar in the upper right. You can take it from here. Restart your email program when you're done.

Step 1.c Gather dice

In the next step, you will need to come up with a secure password. To do that, we recommend that you use dice. The process will be easier for you if you have five dice, but one die will also work.

Step 2.a Make a keypair

The Enigmail Setup wizard may start automatically. If it doesn't, select Enigmail → Setup Wizard from your email program's menu. You don't need to read the text in the window that pops up unless you'd like to, but it's good to read the text on the later screens of the wizard. Click Next with the default options selected, except in these instances:

• On the screen titled "Encryption," select "Encrypt all of my messages by default, because privacy is critical to me."
• On the screen titled "Signing," select "Don't sign my messages by default."
• On the screen titled "Key Selection," select "I want to create a new key pair for signing and encrypting my email."
• On the screen titled "Create Key," pick a strong password! We recommend the Diceware method, which creates passwords which are both strong and memorable. To use the Diceware method, you will need the dice and this list of words. Do not substitute computer dice for physical dice. Notice that each word on the word list corresponds to a unique five-digit number. Role one dice five times, or five dice once to select the first word. Don't rearrange or discard words, because doing so makes the process much less secure. Repeat this process until you have at least six words, and there's your password! Diceware passwords are hard to remember until you've typed it in a handful of times. Write down down your password and keep it with you at all times until you've got it memorized. Then, destroy the piece of paper. If you lose the piece of paper, you will still be able to revoke your key with your revocation certificate (which we'll talk about in just a minute).
• If you don't have dice, pick a password which is at least 12 characters long, and includes at least one lower case and upper case letter and at least one number or punctuation symbol. Don't forget your password, or all of this work will be wasted!

The program will take a little while to finish the next step, the "Key Creation" screen. While you wait, do something else with your computer, like watching a movie or browsing the Web. The more you use the computer at this point, the faster the key creation will go.

When the "Key Generation Completed" screen pops up, select Generate Certificate and choose to save it in a safe place on your computer (we recommend making a folder called "Revocation Certificate" in your home folder and keeping it there). This step is essential for your email self-defense, as you'll learn more about in Section 5.

Step 2.b Upload your public key to a keyserver

In your email program's menu, select Enigmail → Key Management.

Right click on your key and select Upload Public Keys to Keyserver. Use the default keyserver in the popup.

Now someone who wants to send you an encrypted message can download your public key from the Internet. There are multiple keyservers that you can select from the menu when you upload, but they are all copies of each other, so it doesn't matter which one you use. However, it sometimes takes a few hours for them to match each other when a new key is uploaded.

GnuPG, OpenPGP, what?

In general, the terms GnuPG, GPG, GNU Privacy Guard, OpenPGP and PGP are used interchangeably. Technically, OpenPGP (Pretty Good Privacy) is the encryption standard, and GNU Privacy Guard (often shortened to GPG or GnuPG) is the program that implements the standard. Enigmail is a plug-in program for your email program that provides an interface for GnuPG.

Step 3.a Send Edward your public key

This is a special step that you won't have to do when corresponding with real people. In your email program's menu, go to Enigmail → Key Management. You should see your key in the list that pops up. Right click on your key and select Send Public Keys by Email. This will create a new draft message, as if you had just hit the Write button.

Address the message to edward-en@fsf.org. Put at least one word (whatever you want) in the subject and body of the email. Don't send yet.

There should be an icon of a yellow key in the bottom right of the composition window. This means that encryption is on, however, we want this first special message to Edward to be unencrypted. Click the key icon once to turn encryption off. The key should become grey, with a blue dot on it (to alert you that the setting has been changed from the default). Once encryption is off, hit Send.

It may take two or three minutes for Edward to respond. In the meantime, you might want to skip ahead and check out the Use it Well section of this guide. Once he's responded, head to the next step. From here on, you'll be doing just the same thing as when corresponding with a real person.

When you open Edward's reply, Enigmail may prompt you for your password before using your private key to decrypt it.

Step 3.b Send a test encrypted email

Write a new email in your email program, addressed to edward-en@fsf.org. Make the subject "Encryption test" or something similar and write something in the body.

The key in the bottom right of the window should be yellow, meaning encryption is on. This will be your default from now on.

Next to the key, you'll notice an icon of a pencil. Clicking this tells Enigmail to add a special, unique signature to your message, generated using your private key. This is a separate feature from encryption, and you don't have to use it for this guide.

Click Send. Enigmail will pop up a window that says "Recipients not valid, not trusted or not found."

To encrypt an email to Edward, you need his public key, so now you'll have Enigmail download it from a keyserver. Click Download Missing Keys and use the default in the pop-up that asks you to choose a keyserver. Once it finds keys, check the first one (Key ID starting with C), then select ok. Select ok in the next pop-up.

Now you are back at the "Recipients not valid, not trusted or not found" screen. Check the box in front of Edward's key and click Send.

Since you encrypted this email with Edward's public key, Edward's private key is required to decrypt it. Edward is the only one with his private key, so no one except him — not even you — can decrypt it.

Important: Security tips

Even if you encrypt your email, the subject line is not encrypted, so don't put private information there. The sending and receiving addresses aren't encrypted either, so a surveillance system can still figure out who you're communicating with. Also, surveillance agents will know that you're using GnuPG, even if they can't figure out what you're saying. When you send attachments, Enigmail will give you an option of whether you want to encrypt them.

Encryption only works when you use it, so it's a good habit to double-check that email encryption is turned on before you hit send.

Step 3.c Receive a response

When Edward receives your email, he will use his private key to decrypt it, then use your public key (which you sent him in Step 3.A) to encrypt his reply to you.

It may take two or three minutes for Edward to respond. In the meantime, you might want to skip ahead and check out the Use it Well section of this guide.

When you receive Edward's email and open it, Enigmail will automatically detect that it is encrypted with your public key, and then it will use your private key to decrypt it.

Notice the bar that Enigmail shows you above the message, with information about the status of Edward's key.

Step 3.d Send a test signed email to a friend

GnuPG includes a way for you to sign messages and files, verifying that they came from you and that they weren't tampered with along the way. These signatures are stronger than their pen-and-paper cousins -- they're impossible to forge, because they're impossible to create without your private key (another reason to keep your private key safe).

You can sign messages to anyone (including people who haven't created their own keypair!) so it's a great way to promote GnuPG. To sign an email to a friend, click the pencil icon next to the lock icon so that it turns gold.If you sign a message, Enigmail will ask you for your password before it sends the message off. I will do this every time it needs to use your private key.

When the pencil is gold but the lock is grey, the email will be signed but not encrypted. When the pencil is grey and the lock is gold, the email will be encrypted but not signed. When they're both gold, the email will be signed and encrypted.

Step 4.a Sign a key

In your email program's menu, go to Enigmail → Key Management.

Right click on Edward's public key and select Sign Key from the context menu.

In the window that pops up, select "I will not answer" and click ok.

Now you should be back at the Key Management menu. Select Keyserver → Upload Public Keys and hit ok.

You've just effectively said "I trust that Edward's public key actually belongs to Edward." This doesn't mean much because Edward isn't a real person, but it's good practice.

Identifying keys: Fingerprints and IDs

People's public keys are usually identified by their key fingerprint, which is a string of digits like F357AA1A5B1FA42CFD9FE52A9FF2194CC09A61E8 (for Edward's key). You can see the fingerprint for your public key, and other public keys saved on your computer, by going to Enigmail → Key Management in your email program's menu, then right clicking on the key and choosing Key Properties. It's good practice to share your fingerprint wherever you share your email address, so that people can double-check that they have the correct public key when they download yours from a keyserver.

You may also see public keys referred to by their key ID, which is simply the last 8 digits of the fingerprint, like C09A61E8 for Edward. The key ID is visible directly from the Key Management window. This key ID is like a person's first name (it is a useful shorthand but may not be unique to a given key), whereas the fingerprint actually identifies the key uniquely without the possibility of confusion. If you only have the key ID, you can still look up the key (as well as its fingerprint), like you did in Step 3, but if multiple options appear, you'll need the fingerprint of the person to whom you are trying to communicate to verify which one to use.

Important: check people's identification before signing their keys

Before signing a real person's key, always make sure it actually belongs to them, and that they are who they say they are. Ask them to show you their ID (unless you trust them very highly) and their public key fingerprint -- not just the shorter public key ID, which could refer to another key as well. In Enigmail, answer honestly in the window that pops up and asks "How carefully have you verified that the key you are about to sign actually belongs to the person(s) named above?".

When should I encrypt?

The more you can encrypt your messages, the better. If you only encrypt emails occasionally, each encrypted message could raise a red flag for surveillance systems. If all or most of your email is encrypted, people doing surveillance won't know where to start.

That's not to say that only encrypting some of your email isn't helpful -- it's a great start and it makes bulk surveillance more difficult.

Be wary of invalid keys

GnuPG makes email safer, but it's still important to watch out for invalid keys, which might have fallen into the wrong hands. Email encrypted with invalid keys might be readable by surveillance programs.

In your email program, go back to the second email that Edward sent you. Because Edward encrypted it with your public key, it will have a message from Enigmail at the top, which most likely says "Enigmail: Part of this message encrypted."

When using GnuPG, make a habit of glancing at that bar. The program will warn you there if you get an email encrypted with a key that can't be trusted.

Copy your revocation certificate to somewhere safe

Remember when you created your keys and saved the revocation certificate that GnuPG made? It's time to copy that certificate onto the safest digital storage that you have -- the ideal thing is a flash drive, disk, or hard drive stored in a safe place in your home.

If your private key ever gets lost or stolen, you'll need this certificate file to let people know that you are no longer using that keypair.

Important: act swiftly if someone gets your private key

If you lose your private key or someone else gets ahold of it (say, by stealing or cracking your computer), it's important to revoke it immediately before someone else uses it to read your encrypted email. This guide doesn't cover how to revoke a key, but you can follow the instructions on the GnuPG site. After you're done revoking, send an email to everyone with whom you usually use your key to make sure they know.

Webmail and GnuPG

When you use a web browser to access your email, you're using webmail, an email program stored on a distant website. Unlike webmail, your desktop email program runs on your own computer. Although webmail can't decrypt encrypted email, it will still display it in its encrypted form. If you primarily use webmail, you'll know to open your email client when you receive a scrambled email.

Optional: Protect Your Privacy with Tor

The Onion Router (Tor) network wraps Internet communication in multiple layers of encryption and bounces it around the world several times. When used properly, Tor confuses surveillance field agents and the global surveillance apparatus alike. To have your email program send and receive email over Tor, install the Torbirdy plugin the same way you installed Enigmail, by searching for it through Add-ons.

Before beginning to check your email over Tor, make sure you understand the security tradeoffs involved. This infographic demonstrates how Tor keeps you secure.