Trying to protect all your data from everyone all the time is impractical and exhausting. But, do not fear! Security is a process, and through thoughtful planning, you can assess what’s right for you. Security isn’t about the tools you use or the software you download. It begins with understanding the unique threats you face and how you can counter those threats.

In computer security, a threat is a potential event that could undermine your efforts to defend your data. You can counter the threats you face by determining what you need to protect and from whom you need to protect it. This process is called “threat modeling.”

This guide will teach you how to threat model, or how to assess your risks for your digital information and how to determine what solutions are best for you.

What might threat modeling look like? Let’s say you want to keep your house and possessions safe, here are a few questions you might ask:

What do I have inside my home that is worth protecting?

• Assets could include: jewelry, electronics, financial documents, passports, or photos

Who do I want to protect it from?

• Adversaries could include: burglars, roommates, or guests

How likely is it that I will need to protect it?

• Does my neighborhood have a history of burglaries? How trustworthy are my roommates/guests? What are the capabilities of my adversaries? What are the risks I should consider?

How bad are the consequences if I fail?

• Do I have anything in my house that I cannot replace? Do I have the time or money to replace these things? Do I have insurance that covers goods stolen from my home?

How much trouble am I willing to go through to prevent these consequences?

• Am I willing to buy a safe for sensitive documents? Can I afford to buy a high-quality lock? Do I have time to open a security box at my local bank and keep my valuables there?

Once you have asked yourself these questions, you are in a position to assess what measures to take. If your possessions are valuable, but the risk of a break-in is low, then you may not want to invest too much money in a lock. But, if the risk is high, you’ll want to get the best lock on the market, and consider adding a security system.

Building a threat model helps you to understand the unique threats you face, your assets, your adversary, your adversary’s capabilities, and the likelihood of risks you face.

Threat modeling as a regular practice Anchor link

Keep in mind your threat model can change as your situation changes. Thus, conducting frequent threat modeling assessments is good practice.

Create your own threat model based on your own unique situation. Then mark your calendar for a date in the future. This will prompt you to review your threat model and check back in to assess whether it’s still relevant to your situation.

Telecommunication networks and the Internet have made communicating with people easier than ever, but have also made surveillance more prevalent than it has ever been in human history. Without taking extra steps to protect your privacy, every phone call, text message, email, instant message, voice over IP (VoIP) call, video chat, and social media message may be vulnerable to eavesdroppers.

Often the safest way to communicate with others is in person, without computers or phones being involved at all. Because this isn’t always possible, the next best thing is to use end-to-end encryption while communicating over a network if you need to protect the content of your communications.

Voice Calls Anchor link

When you make a call from a landline or a mobile phone, your call is not end-to-end encrypted. If you're using a mobile phone, your call may be (weakly) encrypted between your handset and the cell phone towers. However as your conversation travels through the phone network, it's vulnerable to interception by your phone company and, by extension, any governments or organizations that have power over your phone company. The easiest way to ensure you have end-to-end encryption on voice conversations is to use VoIP instead.

Beware! Most popular VoIP providers, such as Skype and Google Hangouts, offer transport encryption so that eavesdroppers cannot listen in, but the providers themselves are still potentially able to listen in. Depending on your threat model, this may or may not be a problem.

Some services that offer end-to-end encrypted VoIP calls include:

• WhatsApp
• Signal
• Jitsi 
• Silent Phone
• Zphone

In order to have end-to-end encrypted VoIP conversations, both parties must be using the same (or compatible) software.

Instant Messages Anchor link

Off-the-Record (OTR) is an end-to-end encryption protocol for real-time text conversations that can be used on top of a variety of services.

Some tools that incorporate OTR with instant messaging include:

• Pidgin (for Windows or Linux)
• Adium (for OS X)
• ChatSecure (for iPhone and Android)
• Jitsi (Linux, Windows, Mac OS)

What End-To-End Encryption Does Not Do Anchor link

End-to-end encryption only protects the content of your communication, not the fact of the communication itself. It does not protect your metadata—which is everything else, including the subject line of your email, or who you are communicating with and when.

Metadata can provide extremely revealing information about you even when the content of your communication remains secret.

Metadata about your phone calls can give away some very intimate and sensitive information. For example:

• They know you rang a phone sex service at 2:24 am and spoke for 18 minutes, but they don't know what you talked about.
• They know you called the suicide prevention hotline from the Golden Gate Bridge, but the topic of the call remains a secret.
• They know you spoke with an HIV testing service, then your doctor, then your health insurance company in the same hour, but they don't know what was discussed.
• They know you received a call from the local NRA office while it was having a campaign against gun legislation, and then called your senators and congressional representatives immediately after, but the content of those calls remains safe from government intrusion.
• They know you called a gynecologist, spoke for a half hour, and then called the local Planned Parenthood's number later that day, but nobody knows what you spoke about.

If you are calling from a cell phone, information about your location is metadata. In 2009, Green Party politician Malte Spitz sued Deutsche Telekom to force them to hand over six months of Spitz’s phone data, which he made available to a German newspaper. The resulting visualization showed a detailed history of Spitz’s movements.

Protecting your metadata will require you to use other tools, such as Tor, at the same time as end-to-end encryption.

For an example of how Tor and HTTPS work together to protect the contents of your communications and your metadata from a variety of potential attackers, you may wish to take a look at this explanation.

Creating Strong Passwords Using Password Managers Anchor link

Reusing passwords is an exceptionally bad security practice. If a bad actor gets ahold of a password that you've reused across multiple services, they can gain access to many of your accounts. This is why having multiple, strong, unique passwords is so important.

Fortunately, a password manager can help. A password manager is a tool that creates and stores passwords for you, so you can use many different passwords on different sites and services without having to memorize them. Password managers:

• generate strong passwords that a human being would be unlikely to guess.

• store several passwords (and responses to security questions) safely.

• protect all of your passwords with a single master password (or passphrase).

KeePassXC is an example of a password manager that is open-source and free. You can keep this tool on your desktop or integrate it into your web browser. KeePassXC does not automatically save changes you make when using it, so if it crashes after you've added some passwords, you can lose them forever. You can change this in the settings.

Wondering whether a password manager is the right tool for you? If a powerful adversary like a government is targeting you, it might not be.

Remember:

• using a password manager creates a single point of failure.

• password managers are an obvious target for adversaries.

• research suggests that many password managers have vulnerabilities.

If you’re worried about expensive digital attacks, consider something more low-tech. You can create strong passwords manually (see “Creating strong passwords using dice” below), write them down, and keep them somewhere safe on your person.

Wait, aren’t we supposed to keep passwords in our heads and never write them down? Actually, writing them down, and keeping them somewhere like your wallet, is useful so you’ll at least know if your written passwords go missing or get stolen.

A Word About “Security Questions” Anchor link

Beware of the “security questions” that websites use to confirm your identity. Honest answers to these questions are often publicly discoverable facts that a determined adversary can easily find and use to bypass your password entirely.

Instead, give fictional answers that no one knows but you. For example, if the security question asks:

“What was the name of your first pet?”

Your answer could be a random password generated from your password manager. You can store these fictional answers in your password manager.

Think of sites where you’ve used security questions and consider changing your responses. Do not use the same passwords or security question answers for multiple accounts on different websites or services.

Multi-Factor Authentication and One-Time Passwords Anchor link

Strong, unique passwords make it much harder for bad actors to access your accounts. To further protect your accounts, enable two-factor authentication.

Some services offer two-factor authentication (also called 2FA, multi-factor authentication, or two-step verification), which requires users to possess two components (a password and a second factor) to gain access to their account. The second factor could be a one-off secret code or a number generated by a program running on a mobile device.

Two-factor authentication using a mobile phone can be done in one of two ways:

• your phone can run an authenticator application that generates security codes (such as Google Authenticator or Authy) or you can use a stand-alone hardware device (such as a YubiKey); or
• the service can send you an SMS text message with an extra security code that you need to type in whenever you log in.

If you have a choice, pick the authenticator application or stand-alone hardware device instead of receiving codes by text message. It’s easier for an attacker to redirect these codes to their own phone than it is to bypass the authenticator.

Some services, such as Google, also allow you to generate a list of one-time passwords, also called single-use passwords. These are meant to be printed or written down on paper and carried with you. Each of these passwords works only once, so if one is stolen by spyware when you enter it, the thief won't be able to use it for anything in the future.

If you or your organization run your own communications infrastructure, there's free software available that can be used to enable two-factor authentication for accessing your systems. Look for software offering implementations of the open standard “Time-Based One-Time Passwords” or RFC 6238.

Most of us think that a file on our computer is deleted once we put the file in our computer's trash folder and empty the trash; in reality, deleting the file does not completely erase it. When one does this, the computer just makes the file invisible to the user and marks the part of the disk that the file was stored on as "available”—meaning that your operating system can now write over the file with new data. Therefore, it may be weeks, months, or even years before that file is overwritten with a new one. Until this happens, that “deleted” file is still on your disk; it’s just invisible to normal operations. And with a little work and the right tools (such as “undelete” software or forensic methods), you can even still retrieve the “deleted” file. The bottom line is that computers normally don't "delete" files; they just allow the space those files take up to be overwritten by something else some time in the future.

The best way to delete a file forever, then, is to make sure it gets overwritten immediately, in a way that makes it difficult to retrieve what used to be written there. Your operating system probably already has software that can do this for you—software that can overwrite all of the "empty" space on your disk with gibberish and thereby protect the confidentiality of deleted data.

Note that securely deleting data from solid state drives (SSDs), USB flash drives, and SD cards is very hard! The instructions below apply only to traditional disk drives, and not to SSDs, which are becoming standard in modern laptops, USB keys/USB thumb drives, or SD cards/flash memory cards.

This is because these types or drives use a technique called wear leveling. (You can read more about why this causes problems for secure deletion here.)

If you’re using an SSD or a USB flash drive, you can jump to the section below.

A Warning About the Limitations of Secure Deletion Tools Anchor link

First, remember that the advice above only deletes files on the disk of the computer you’re using. None of the tools above will delete backups that were made to somewhere else on your computer, another disk or USB drive, a “Time Machine,” on an email server, or in the cloud. In order to securely delete a file, you must delete every copy of that file, everywhere it was stored or sent. Additionally, once a file is stored in the cloud (e.g. via Dropbox or some other file-sharing service) then there’s usually no way to guarantee that it will be deleted forever.

Unfortunately, there’s also another limitation to secure deletion tools. Even if you follow the advice above and you’ve deleted all copies of a file, there is a chance that certain traces of deleted files may persist on your computer, not because the files themselves haven't been properly deleted, but because some part of the operating system or some other program keeps a deliberate record of them.

There are many ways in which this could occur, but two examples should suffice to convey the possibility. On Windows or Mac OS, a copy of Microsoft Office may retain a reference to the name of a file in the "Recent Documents" menu, even if the file has been deleted (Office might sometimes even keep temporary files containing the contents of the file). On a Linux or other *nix system, OpenOffice may keep as many records as Microsoft Office, and a user's shell history file may contain commands that include the file's name, even though the file has been securely deleted. In practice, there may be dozens of programs that behave like this.

It's hard to know how to respond to this problem. It is safe to assume that even if a file has been securely deleted, its name will probably continue to exist for some time on your computer. Overwriting the entire disk is the only way to be 100% sure the name is gone. Some of you may be wondering, "Could I search the raw data on the disk to see if there are any copies of the data anywhere?" The answer is yes and no. Searching the disk (e.g. by using a command like grep -ab /dev/ on Linux) will tell you if the data is present in plaintext, but it won't tell you if some program has compressed or otherwise coded references to it. Also be careful that the search itself does not leave a record! The probability that the file's contents may persist is lower, but not impossible. Overwriting the entire disk and installing a fresh operating system is the only way to be 100% certain that records of a file have been erased.

Discarding CD-ROMS Anchor link

When it comes to CD-ROMs, you should do the same thing you do with paper―shred them. There are inexpensive shredders that will chew up CD-ROMs. Never just toss a CD-ROM out in the garbage unless you're absolutely sure there's nothing sensitive on it.

Most of us think that a file on our computer is deleted once we put the file in our computer's trash folder and empty the trash; in reality, deleting the file does not completely erase it. When one does this, the computer just makes the file invisible to the user and marks the part of the disk that the file was stored on as "available”—meaning that your operating system can now write over the file with new data. Therefore, it may be weeks, months, or even years before that file is overwritten with a new one. Until this happens, that “deleted” file is still on your disk; it’s just invisible to normal operations. And with a little work and the right tools (such as “undelete” software or forensic methods), you can even still retrieve the “deleted” file. The bottom line is that computers normally don't "delete" files; they just allow the space those files take up to be overwritten by something else some time in the future.

The best way to delete a file forever, then, is to make sure it gets overwritten immediately, in a way that makes it difficult to retrieve what used to be written there. Your operating system probably already has software that can do this for you—software that can overwrite all of the "empty" space on your disk with gibberish and thereby protect the confidentiality of deleted data.

Note that securely deleting data from solid state drives (SSDs), USB flash drives, and SD cards is very hard! The instructions below apply only to traditional disk drives, and not to SSDs, which are becoming standard in modern laptops, USB keys/USB thumb drives, or SD cards/flash memory cards.

This is because these types or drives use a technique called wear leveling. (You can read more about why this causes problems for secure deletion here.)

If you’re using an SSD or a USB flash drive, you can jump to the section below.

On Windows, we currently suggest using BleachBit. BleachBit is a free/open source secure deletion tool for Windows and Linux, and is much more sophisticated than the built-in Cipher.exe.

BleachBit can be used to quickly and easily target individual files for secure deletion, or to implement periodic secure deletion policies. It is also possible to write custom file deletion instructions. Please check the documentation for further information.

Installing BleachBit Anchor link

Keep the Windows Explorer window open and double-click on BleachBit-1.6-setup. You'll be asked if you want to allow the installation of this program. Click the “Yes” button.

A window will open asking you to select an installation language. Select the language you want and click the OK button.

The next window will show you the GNU General Public License. Check the box acceptance box and click the Next button.

In the next window BleachBit shows some customization options. You may leave the options as they are. We recommend removing the check mark from the Desktop option. Click the Next button.

Now BleachBit will ask you to confirm whether you want to install again. Click the Install button.

Finally, the BleachBit installer shows a window telling you the installation is complete. Click the Next button.

The last window in the installer asks whether you want to run BleachBit. Remove the checkmark from the Run BleachBit option. Click the Finish button.

A Warning About the Limitations of Secure Deletion Tools Anchor link

First, remember that the advice above only deletes files on the disk of the computer you’re using. None of the tools above will delete backups that were made to somewhere else on your computer, another disk or USB drive, a “Time Machine,” on an email server, or in the cloud. In order to securely delete a file, you must delete every copy of that file, everywhere it was stored or sent. Additionally, once a file is stored in the cloud (e.g. via Dropbox or some other file-sharing service) then there’s usually no way to guarantee that it will be deleted forever.

Unfortunately, there’s also another limitation to secure deletion tools. Even if you follow the advice above and you’ve deleted all copies of a file, there is a chance that certain traces of deleted files may persist on your computer, not because the files themselves haven't been properly deleted, but because some part of the operating system or some other program keeps a deliberate record of them.

There are many ways in which this could occur, but two examples should suffice to convey the possibility. On Windows or Mac OS, a copy of Microsoft Office may retain a reference to the name of a file in the "Recent Documents" menu, even if the file has been deleted (Office might sometimes even keep temporary files containing the contents of the file). On a Linux or other *nix system, OpenOffice may keep as many records as Microsoft Office, and a user's shell history file may contain commands that include the file's name, even though the file has been securely deleted. In practice, there may be dozens of programs that behave like this.

It's hard to know how to respond to this problem. It is safe to assume that even if a file has been securely deleted, its name will probably continue to exist for some time on your computer. Overwriting the entire disk is the only way to be 100% sure the name is gone.

Discarding CD-ROMS Anchor link

When it comes to CD-ROMs, you should do the same thing you do with paper―shred them. There are inexpensive shredders that will chew up CD-ROMs. Never just toss a CD-ROM out in the garbage unless you're absolutely sure there's nothing sensitive on it.

Most of us think that a file on our computer is deleted once we put the file in our computer's trash folder and empty the trash; in reality, deleting the file does not completely erase it. When one does this, the computer just makes the file invisible to the user and marks the part of the disk that the file was stored on as "available”—meaning that your operating system can now write over the file with new data. Therefore, it may be weeks, months, or even years before that file is overwritten with a new one. Until this happens, that “deleted” file is still on your disk; it’s just invisible to normal operations. And with a little work and the right tools (such as “undelete” software or forensic methods), you can even still retrieve the “deleted” file. The bottom line is that computers normally don't "delete" files; they just allow the space those files take up to be overwritten by something else some time in the future.

The best way to delete a file forever, then, is to make sure it gets overwritten immediately, in a way that makes it difficult to retrieve what used to be written there. Your operating system probably already has software that can do this for you—software that can overwrite all of the "empty" space on your disk with gibberish and thereby protect the confidentiality of deleted data.

Note that securely deleting data from solid state drives (SSDs), USB flash drives, and SD cards is very hard! The instructions below apply only to traditional disk drives, and not to SSDs, which are becoming standard in modern laptops, USB keys/USB thumb drives, or SD cards/flash memory cards.

This is because these types or drives use a technique called wear leveling. (You can read more about why this causes problems for secure deletion here.)

If you’re using an SSD or a USB flash drive, you can jump to the section below.

On Linux, we currently suggest using BleachBit. BleachBit is an open-source secure deletion tool for Windows and Linux, and is much more sophisticated than the built-in “shred.”

BleachBit can be used to quickly and easily target individual files for secure deletion, or to implement periodic secure deletion policies. It is also possible to write custom file deletion instructions. Please check the documentation for further information.

Installing From the Terminal Anchor link

You can get BleachBit on Ubuntu Linux by using the Terminal. Click on the Application button in the upper left menu and use the search field. 

Type “sudo apt-get install bleachbit” and press the Enter.

You are asked to enter your password to verify that you want to install BleachBit. Enter your password and press Enter.

Now you'll see the progress of the installation of BleachBit and when it is done you should be back at the command line where you started.

Using BleachBit Anchor link

Click on the Application button in the upper left menu and click on BleachBit from the favorites.

The main BleachBit window will open.

First BleachBit gives us an overview of the preferences. We recommend checking the “Overwrite files to hide contents” option.

Click the Close button.

BleachBit will detect several commonly installed programs and will show special option for each program. BleachBit comes with four default settings.

Using Presets

Some software leaves behind records of when and how it was used. Two important examples that merely begin to illustrate this widespread issue are Recent Documents and web browser history. Software that tracks the recently-edited documents leaves a record of the names of files you've been working with, even if those files themselves have been deleted. And web browsers usually keep detailed records of what sites you've visited recently, and even keep cached copies of pages and images from those sites to make them load faster next time you visit.

Bleachbit provides "presets" that can remove some of these records for you, based on the Bleachbit authors' research about locations of records on your computer that tend to reveal your previous activity. We'll describe using just two of these presets so you can get an idea of how they work.

Check the box next to System. Notice that this marks all the checkboxes under the System category. Uncheck the System box and check the following boxes: Recent document list and Trash. Click the Clean button.

BleachBit will now ask you for confirmation. Click the Delete button.

BleachBit will now clean up certain files and show you the progress.

Securely Delete a Folder

Click the File menu and select Shred Folders.

A small window will open up. Select the folder you want to shred.

BleachBit will ask you to confirm whether you want to permanently delete the files you selected. Click the Delete button.

BleachBit will now show you the files you deleted. Notice that BleachBit securely deletes each file in the folder, then securely deletes the folder.

Securely Delete a File

Click the File menu and select Shred Files.

A file selection window will open up. Select the files you want to shred.

BleachBit will ask you to confirm whether you want to permanently delete the files you selected. Click the Delete button.

Secure Deletion When Discarding Old Hardware Anchor link

If you want to finally throw a piece of hardware away or sell it on eBay, you'll want to make sure no one can retrieve your data from it. Studies have repeatedly found that computer owners usually fail to do this―hard drives are often resold chock-full of highly sensitive information. So, before selling or recycling a computer, be sure to overwrite its storage media with gibberish first. And even if you're not getting rid of it right away, if you have a computer that has reached the end of its life and is no longer in use, it's also safer to wipe the hard drive before stashing the machine in a corner or a closet. Darik's Boot and Nuke is a tool designed for this purpose, and there are a variety of tutorials on how to use it across the web (including here).

Some full-disk encryption software has the ability to destroy the master key, rendering a hard drive's encrypted contents permanently incomprehensible. Since the key is a tiny amount of data and can be destroyed almost instantaneously, this represents a much faster alternative to overwriting with software like Darik's Boot and Nuke, which can be quite time-consuming for larger drives. However, this option is only feasible if the hard drive was always encrypted. If you weren't using full-disk encryption ahead of time, you'll need to overwrite the whole drive before getting rid of it.

Secure Deletion on Solid-state Disks (SSDs), USB Flash Drives, and SD Cards Anchor link

Unfortunately due to the way SSDs, USB flash drives, and SD cards work, it is difficult, if not impossible, to securely delete both individual files and free space. As a result your best bet in terms of protection is to use encryption—that way, even if the file is still on the disk, it will at least look like gibberish to anyone who gets ahold of it and can’t force you to decrypt it. At this point in time, we cannot provide a good general procedure that will definitely remove your data from an SSD. If you want to know why it’s so hard to delete data, read on.

As we mentioned above, SSDs and USB flash drives use a technique called wear leveling. At a high level, wear leveling works as follows. The space on every disk is divided into blocks, kind of like the pages in a book. When a file is written to disk, it’s assigned to a certain block or set of blocks (pages). If you wanted to overwrite the file then all you would have to do is tell the disk to overwrite those blocks. But in SSDs and USB drives, erasing and re-writing the same block can wear it out. Each block can only be erased and rewritten a limited number of times before that block just won’t work anymore (the same way if you keep writing and erasing with a pencil and paper, eventually the paper might rip and be useless). To counteract this, SSDs and USB drives will try to make sure that the amount of times each block has been erased and rewritten is about the same, so that the drive will last as long as possible (thus the term wear leveling). As a side effect, sometimes instead of erasing and writing the block a file was originally stored on, the drive will instead leave that block alone, mark it as invalid, and just write the modified file to a different block. This is kind of like leaving the page in the book unchanged, writing the modified file on a different page, and then just updating the book’s table of contents to point to the new page. All of this occurs at a very low level in the electronics of the disk, so the operating system doesn’t even realize it’s happened. This means, however, that even if you try to overwrite a file, there’s no guarantee the drive will actually overwrite it—and that’s why secure deletion with SSDs is so much harder.

One of the greatest challenges of defending your data from those who might want it is the sheer size of the information you store or carry, and the ease by which it can be taken from you. Many of us carry entire histories of our contacts, our communications, and our current documents on laptops, or even mobile phones. That data can include confidential information of dozens, even thousands, of people. A phone or laptop can be stolen, or copied in seconds.

The United States is just one of many countries that seizes and copies data at borders. Data can be taken from you at roadblocks, grabbed from you in the street, or burgled from your house.

Just as you can keep your communications safer with encryption, you can also make it harder for those who physically steal data to unlock its secrets. Computers and mobile phones can be locked by passwords, PINs or gestures, but these locks do not help protect data if the device itself is seized. It's relatively simple to bypass these locks, because your data is stored in an easily readable form within the device. All an attacker needs to do is to access the storage directly, and the data can be copied or examined without knowing your password.

If you use encryption, your adversary needs not just your device, but also your password to unscramble the encrypted data—there's no shortcut.

It's safest and easiest to encrypt all of your data, not just a few folders. Most computers and smartphones offer complete, full-disk encryption as an option. Android offers it under its "Security" settings, Apple devices such as the iPhone and iPad describe it as "Data Protection" and turn it on if you set a passcode. On computer running Windows Pro, it's known as "BitLocker." 

BitLocker's code is closed and proprietary, which means it is hard for external reviewers to know exactly how secure it is. Using BitLocker requires you trust Microsoft provides a secure storage system without hidden vulnerabilities. On the other hand, if you're already using Windows, you are already trusting Microsoft to the same extent. If you are worried about surveillance from the kind of attackers who might know of or benefit from a back door in either Windows or BitLocker, you may wish to consider an alternative open-source operating system such as GNU/Linux or BSD, especially a version that has been hardened against security attacks, such Tails or Qubes OS.

Apple provides a built-in full disk encryption feature on macOS called FileVault.  On Linux distributions, full-disk encryption is usually offered when you first set up your system. At the time this guide was updated, we do not have a full disk encryption tool for versions of Windows that do not include BitLocker that we can recommend.

Whatever your device calls it, encryption is only as good as your password. If your attacker has your device, they have all the time in the world to try out new passwords. Forensic software can try millions of passwords a second. That means that a four number pin is unlikely to protect your data for very long at all, and even a long password may merely slow down your attacker. A really strong password under these conditions should be over fifteen characters long.

Most of us are not realistically going to learn and enter such passphrases on our phones or mobile devices. So while encryption can be useful to prevent casual access, you should preserve truly confidential data by keeping it hidden from physical access by attackers, or cordoned away on a much more secure machine.

Social networking sites are some of the most popular websites and tools we use on the Internet. Facebook, Google+, and Twitter have hundreds of millions of users each.

Social networks are often built on the idea of sharing posts, photographs, and personal information. Yet they have also become forums for organizing and speech—much of which relies on privacy and pseudonymity. Thus, the following questions are important to consider when using social networks: How can I interact with these sites while protecting myself? My basic privacy? My identity? My contacts and associations? What information do I want keep private and who do I want to keep it private from?

Depending on your circumstances, you may need to protect yourself against the social media site itself, against other users of the site, or both.

Here are some tips to keep in mind when you’re setting up your account:

Check the Social Media Site's Privacy Policy Anchor link

Remember that information stored by third parties is subject to their own policies and may be used for commercial purposes or shared with other companies, for example, marketing firms. We know that reading privacy policies is a near-impossible task, but you may want to take a look at sections on how your data is used, when it is shared with other parties, and how the service responds to law enforcement requests.

Social networking sites, usually for-profit businesses, often collect sensitive information beyond what you explicitly input—where you are, what interests and advertisements you react to, what other sites you've visited (e.g. through "Like" buttons). It can be helpful to block third-party cookies and use tracker-blocking browser extensions to make sure extraneous information isn't being passively transmitted to third parties.

Some social networking sites, like Facebook and Twitter, have business relationships with data brokers in order to target advertisements more effectively. EFF has guides that walk you through how to opt-out of these tracking schemes:

• How to opt-out of Facebook's data broker relationships
• How to opt-out of Twitter's data broker relationships

Your Social Graph Anchor link

Remember that you’re not the only person who can give away potentially sensitive data about yourself. Your friends can tag you in photos, report your location, and make their connections to you public in a variety of ways. You may have the option of untagging yourself from these posts, but privacy does not work retroactively. You may want to talk to your friends about what you do and do not feel comfortable having them share about you in public.

This is a short overview to circumventing online censorship, but is by no means comprehensive.

Governments, companies, schools, and Internet providers sometimes use software to prevent their users from accessing certain websites and services. This is called Internet filtering or blocking, and it is a form of censorship. Filtering comes in different forms. Censors can block individual web pages, or even entire websites. Sometimes, content is blocked based on the keywords it contains.

There are different ways of beating Internet censorship. Some protect you from surveillance, but many do not. When someone who controls your net connection filters or blocks a site, you can almost always use a circumvention tool to get to the information you need. Note: Circumvention tools that promise privacy or security are not always private or secure. And tools that use terms like “anonymizer” do not always keeps your identity completely secret.

The circumvention tool that is best for you depends on your threat model. If you’re not sure what your threat model is, start here.

In this article, we'll talk about four ways to circumvent censorship:

• Visiting a web proxy to access a blocked website.
• Visiting an encrypted web proxy to access a blocked website.
• Using a Virtual Private Network (VPN) to access blocked websites or services.
• Using the Tor Browser to access a blocked website or protect your identity.

Web-based proxies Anchor link

A web-based proxy (such as http://proxy.org/) is a website that lets its users access other blocked or censored websites. It is therefore a good way to circumvent censorship. In order to use a web-based proxy, visit the proxy and enter the web address that you want to see; the proxy will then display the web page you asked for.

However, web-based proxies don’t provide any security and will be a poor choice if your threat model includes someone monitoring your internet connection. They will not help you to use blocked services such as your instant messaging apps. The web-based proxy will have a complete record of everything you do online, which can be a privacy risk for some users depending on their threat model.

Virtual Private Networks Anchor link

A Virtual Private Network (VPN) encrypts and sends all Internet data from your computer through another computer. This computer could belong to a commercial or nonprofit VPN service, your company, or a trusted contact. Once a VPN service is correctly configured, you can use it to access webpages, e-mail, instant messaging, VoIP, and any other Internet service. A VPN protects your traffic from being spied on locally, but your VPN provider can still keep logs of the websites you access, or even let a third party snoop directly on your web browsing. Depending on your threat model, the possibility of a government listening in on your VPN connection or getting hold of VPN logs may be a significant risk. For some users, this could outweigh the short-term benefits of using a VPN.

For information about specific VPN services, click here.

We at EFF cannot vouch for this rating of VPNs. Some VPNs with exemplary privacy policies could be run by devious people. Do not use a VPN that you do not trust.

Encryption is the mathematical science of codes, ciphers, and secret messages. Throughout history, people have used encryption to send messages to each other that (hopefully) couldn't be read by anyone besides the intended recipient.

Today, we have computers that are capable of performing encryption for us. Digital encryption technology has expanded beyond simple secret messages; today, encryption can be used for more elaborate purposes, for example to verify the author of messages or to browse the Web anonymously with Tor.

Under some circumstances, encryption can be fairly automatic and simple. But there are ways encryption can go wrong, and the more you understand it, the safer you will be against such situations.