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Email Self-Defense - a guide to fighting surveillance with GnuPG
EMAIL SELF-DEFENSE GNU/LINUX MAC OS WINDOWS
#EMAILSELFDEFENSE
Email Self-Defense is a project of the Free Software Foundation. We fight for computer user's rights, and promote the development of free (as in freedom) software like GnuPG, which is used in this guide. We have big plans to get this guide in the hands of people under bulk surveillance all over the world, and to make more tools like it. Can you make a donation to help us achieve these goals?
Bulk surveillance violates our fundamental rights and makes free speech risky. This guide will teach you a basic surveillance self-defense skill: email encryption. Once you've finished, you'll be able to send and receive emails that are coded to make sure that a surveillance agent or thief can't intercept your email and read it. Even if you have nothing to hide, using encryption helps protect the privacy of people you communicate with, and makes life difficult for bulk surveillance systems. If you do have something important to hide, you're in good company; these are the same tools that Edward Snowden used to share his famous secrets about the NSA. https://emailselfdefense.fsf.org/
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This guide relies on software which is freely licensed; it's completely transparent and anyone can copy it or make their own version. This makes it safer from surveillance than proprietary software (like Windows). Learn more about free software at fsf.org. Let's get started!
#1 GET THE PIECES All you need to start is a computer with an Internet connection, an email account and about half an hour. You can use your existing email account for this without affecting it. Most GNU/Linux operating systems come with GnuPG installed on them, so you don't have to download it. Before configuring GnuPG though, you'll need a desktop email program installed on your computer. Most GNU/Linux distributions have a free software version of the Thunderbird email program available to install. This guide will work with https://emailselfdefense.fsf.org/
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them, in addition to Thunderbird itself. Email programs are another way to access the same email accounts you can access in a browser (like GMail), but provide extra features. If you are already have one of these, you can skip to Step 1.b.
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STEP 1.A SET YOUR EMAIL PROGRAM UP WITH YOUR EMAIL ACCOUNT (IF IT ISN'T ALREADY) Open your email program and follow the wizard that sets it up with your email account. TR O UB LESHO O TING â–ž
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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.
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TR O UB LESHO O TING â–ž
#2 MAKE YOUR KEYS To use the GnuPG system, you'll need a public key and a private key (known together as a keypair). Each is a long string of randomly generated numbers that are unique to you. Your public and private keys are linked together by a special mathematical function. Your public key isn't like a physical key, because it's stored in the open in an online directory called a keyserver. People download it and use it, along with GnuPG, to encrypt emails they send to you. You can think of the keyserver as phonebook, where people who want to send you an encrypted email look up your public key. Your private key is more like a physical key, because you keep it to yourself (on your computer). You use GnuPG and your private key to decode encrypted emails other people send to you.
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STEP 2.A MAKE A KEYPAIR In your email program's menu, select OpenPGP → Setup Wizard. 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. On the second screen, titled "Signing," select "No, I want to create per-recipient rules for emails that need to be signed." https://emailselfdefense.fsf.org/
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Use the default options until you reach the screen titled "Create Key". On the screen titled "Create Key," pick a strong password! Your password should be at least 12 characters and include at least one lower case and upper case letter and at least one number or punctuation symbol. Don't forget the password, or all 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 OpenPGP Confirm 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. You'll learn more about the revocation certificate in Section 5. The setup wizard will ask you to move it onto an external device, but that isn't necessary at this moment. After creating your key, the Enigmail set-up wizard automatically uploaded it to a keyserver, an online computer that makes everyone's keys available through the Internet. TR O UB LESHO O TING ▾
STEP 2.B UPLOAD YOUR PUBLIC KEY TO A KEYSERVER In your email program's menu, select OpenPGP → 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. TR O UB LESHO O TING ▾
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#3 TRY IT OUT! Now you'll try a test correspondence with a computer program named Adele, which knows how to use encryption.
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STEP 3.A SEND ADELE 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 OpenPGP → 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 adele-en@gnupp.de. Put at least one word (whatever you want) in the subject and body of the email, then hit send. https://emailselfdefense.fsf.org/
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It may take two or three minutes for Adele to respond. In the meantime, you might want to skip ahead and check out the Use it Well section of this guide. Once she'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.
STEP 3.B SEND A TEST ENCRYPTED EMAIL Write a new email in your email program, addressed to adele-en@gnupp.de. Make the subject "Encryption test" or something similar and write something in the body. Don't send it yet. Click the icon of the key in the bottom right of the composition window (it should turn yellow). This tells Enigmail to encrypt the email with the key you downloaded in the last step. Click Send. Enigmail will pop up a window that says "Recipients not valid, not trusted or not found." To encrypt and email to Adele, you need her public key, and 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 9), 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. Select Adele's key from the list and click Ok. If the message doesn't send automatically, you can hit send now. TR O UB LESHO O TING â–ž
IMPORTANT: SUBJECT LINES ARE NOT ENCRYPTED Even if you encrypted your email, the subject line is not encrypted, so don't put private information there. The sending and https://emailselfdefense.fsf.org/
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receiving addresses aren't encrypted either, so they could be read by a surveillance system.
STEP 3.C RECEIVE A RESPONSE When Adele receives your email, she will use her private key to decrypt it, then fetch your public key from a keyserver and use it to encrypt a response to you. Since you encrypted this email with Adele's public key, Adele's private key is required to decrypt it. Adele is the only one with her private key, so no one except her — not even you — can decrypt it. It may take two or three minutes for Adele 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 Adele'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 Adele's key.
#4 LEARN THE WEB OF TRUST Email encryption is a powerful technology, but it has a weakness; it requires a way to verify that a person's public key is actually theirs. Otherwise, there would be no way to https://emailselfdefense.fsf.org/
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stop an attacker from making an email address with your friend's name, creating keys to go with it and impersonating your friend. That's why the free software programmers that developed email encryption created keysigning and the Web of Trust. When you sign someone's key, you are publicly saying that you trust that it does belong to them and not an impostor. People who use your public key can see the number of signatures it has. Once you've used GnuPG for a long time, you may have hundreds of signatures. The Web of Trust is the constellation of all GnuPG users, connected to each other by chains of trust expressed through signatures, into a giant Web. The more signatures a key has, and the more signatures its signers' keys have, the more trustworthy that key is. People's public keys are usually identified by their key ID, which is a short string of 8 digits like 92AB3FF7 (for Adele's key). You can see your key ID on the right in OpenPGP → Key Management in your email program's menu. It's good practice to share your key ID, so that 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 fingerprint, which is a longer string of digits, like DD878C06E8C2BEDDD4A440D3E573346992AB3FF7. The key ID is just the last 8 digits of the fingerprint.
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STEP 4.A SIGN A KEY In your email program's menu, go to OpenPGP → Key Management. Right click on Adele'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. https://emailselfdefense.fsf.org/
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In your email program's menu, go to OpenPGP → Key Management → Keyserver → Upload Public Keys and hit OK. You've just effectively said "I trust that Adele's public key actually belongs to Adele." This doesn't mean much because Adele isn't a real person, but it's good practice.
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 they are who they say they are. 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?".
#5 USE IT WELL Everyone uses GnuPG a little differently, but it's important to follow some basic practices to keep your email secure. Not following them, you risk the privacy of the people you communicate with, as well as your own, and damage the Web of Trust.
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WHEN SHOULD I ENCRYPT? The more you can encrypt your messages, the better. This is because, 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.
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IMPORTANT: 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 Adele sent you. Because it was encrypted with her key, it will have a message from OpenPGP at the top, which most likely says "OpenPGP: 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 https://emailselfdefense.fsf.org/
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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 cerfiticate that GnuPG made? It's time to copy that cerfiticate 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.
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.
MAKE YOUR PUBLIC KEY PART OF YOUR ONLINE IDENTITY First add your key ID to your email signature, then compose an email to at least five of your friends, telling them you just set up GnuPG and mentioning your key ID. Link to this guide and ask them to join you. Don't forget that there's also an awesome infographic to share. Start writing your key ID anywhere someone would see your email address: your social media profiles, blog, Website, or https://emailselfdefense.fsf.org/
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business card. (At the Free Software Foundation, we put ours on our staff page.) We need to get our culture to the point that we feel like something is missing when we see an email address without a public key ID.
#6 NEXT STEPS You've now completed the basics of email encryption with GnuPG, taking action against bulk surveillance. A pat on the back to you! Want to do more to secure privacy for yourself and the people you communicate with?
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GO TO A KEYSIGNING PARTY Keysigning parties are social events designed to build the Web of Trust. Participants match each others' photo IDs and key IDs, and then get out their laptops and sign each other's public keys. They're a great way to meet likeminded people and learn about new privacy tools, as well as build up people's trust in your key. Look for keysignings at tech events, hackerspaces and nerdy parties.
WORK FOR POLITICAL CHANGE Encrypting our email is a powerful direct action, but to change the system, we also have to go to the root. One of the key https://emailselfdefense.fsf.org/
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things needed is reducing the amount of data collected about us in the first place. To learn more and participate in efforts for change, join the Free Software Foundation's low-traffic mailing list. Type your email...
SUB SCR IB E M E
Read our Privacy Policy
PROTECT MORE OF YOUR DIGITAL LIFE Learn surveillance-resistant technologies for instant messages, hard drive storage, online sharing and more at the Free Software Directory's Privacy Pack and prism-break.org.
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MAKE EMAIL SELF-DEFENSE TOOLS EVEN BETTER Leave feedback and suggest improvements to this guide, or email us at campaigns@fsf.org if you'd like to help maintain or translate it. If you like programming, you can contribute code to GnuPG or Enigmail. If you can't do any of these, please donate to the Free Software Foundation so we can get Email Self-Defense into the hands of as many people as possible, and make more tools like it.
Copyright © 2014 Free Software Foundation, Inc. Privacy Policy. Join. The images on this page are under a Creative Commons Attribution 4.0 license (or later version), and the rest of it is under a Creative Commons Attribution-ShareAlike 4.0 license (or later version). — Why these licenses? Fonts used in the guide & infographic: Dosis by Pablo Impallari, Signika by Anna Giedryś Archivo Narrow by Omnibus-Type, PXL-2000 by Florian Cramer. Infographic and guide design by Journalism++
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