Blogs

Tor at the Heart: Onion Messaging

During the month of December, we're highlighting other organizations and projects that rely on Tor, build on Tor, or are accomplishing their missions better because Tor exists. Check out our blog each day to learn about our fellow travelers. And please support the Tor Project! We're at the heart of Internet freedom.
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The Internet was made for humans to communicate with each other! Even though Internet calls over video and audio are totally possible nowadays, people still enjoy sending texts to each other due to their asynchronous, permanent and casual nature. To understand how important these instant messaging systems are, just check the user growth of systems like WeChat, WhatsApp, etc.





Unfortunately, all these major mainstream messaging systems belong to huge companies whose money comes from advertising and selling the data and metadata of their users.

The good news here is that in the past couple of years, there has been great progress in protecting users' data by employing end-to-end encryption using the Signal protocol. The bad news is that there has still been absolutely no progress in protecting the metadata and location information of users by these mainstream platforms.

Case in point, since most instant messaging systems are not anonymous, they get to learn the full location history of their users through the users' IP address history. Also, all major chat systems require a social media account or a phone number, which is simply impossible for some people, and it also makes it hard to create anonymous or burner accounts for everyone. It also makes you searchable and targettable by people who happen to know your phone number.

In this blog post, we showcase a few open-source text messaging tools that provide location privacy and additional security to their users by using Tor as a default. All of them are free and open source, so feel free to experiment!

Ricochet

Ricochet is an anonymous instant messaging tool that hides metadata by using Tor. It's got a slick UI and works on Windows, Linux and Mac OS X.

In the Ricochet protocol, each user is a Tor onion service. By utilizing onion services, the protocol achieves strong anonymity for its users. And because of its decentralized nature, it's impossible for attackers to censor it by taking down a single server.

Ricochet is designed with UX in mind, so it's easily usable even by people who don't understand how Tor works.





Chatsecure

If you happen to only use mobile platforms (like most of the world these days), Chatsecure is an app that you should check out! It works for both Android and iOS, and it allows you to connect to XMPP servers to communicate over encrypted OTR chat. This means that you can also use it to connect to other XMPP-enabled messaging systems like Facebook chat and Google Talk.

It's developed by the Guardian Project, and it's a part of their software suite for private communications that includes Orbot and Orfox. Stay tuned on our blog for more information about this software family later this December!





And now for further excitement, let's get into the more experimental sections of the secure messaging space!

Pond

Pond is an anonymous instant messaging tool with various sophisticated security properties that is capable of hiding even the metadata of its users.

The protocol is designed in such a way that even a nasty attacker who is constantly monitoring your Internet connection will have a very hard time figuring out when you actually send and receive Pond messages, even if she conducts statistical analysis of your traffic patterns. Smoke and mirrors you might say, but if you like protocols, we invite you to check out the Pond protocol specs.

Unfortunately, Pond is a side-project, and due to lack of free time, the project is not currently actively being developed, even though there is still a community of users. It only works on Linux, and it has a GUI interface.





Briar

Briar is an experimental P2P messaging system that is currently in private beta. It targets mobile users and is closely integrated with Tor onion services.

The Briar protocol is fully decentralized, and all communication is end-to-end encrypted. It aims to be highly resilient against network failures, and so it can also function over Bluetooth or WiFi. Furthermore, it attempts to hide the social graph of its users by keeping the user contact list on the client side.





Future directions

As you can see, there have been multiple efforts for private and metadata-hiding communication over the past years. Some of these projects are supposed to be used on top of already existing chat frameworks, whereas others aim to create their own ecosystems.

Of course, the research realm of secure messaging is far from complete; it's just getting started. From improving the UX to adding new security properties, this field needs further thinking all around.

For example, secure multiparty messaging is a very important upcoming field that studies how the protocols above that are designed for 1-to-1 communication can scale to hundreds of clients talking at the same time while maintaining their security properties.

Furthermore, as global surveillance is growing, we better understand the importance of hiding metadata from network attackers. Only now are we starting to grasp the importance of security properties like obfuscating communication patterns, hiding the users' social graph and letting users choose when to reveal their online presence.

Tor is extremely interested in the instant messaging space, and we are always on the lookout for innovative developments and interesting messaging projects. We have deep gratitude to all of the people who have helped to push the field of secure messaging forward, and we hope to enable them in the future to provide anonymous communication tools!

Donate and we will make it happen! :)

Tor at the Heart: Bridges and Pluggable Transports

During the month of December, we're highlighting other organizations and projects that rely on Tor, build on Tor, or are accomplishing their missions better because Tor exists. Check out our blog each day to learn about our fellow travelers. And please support the Tor Project! We're at the heart of Internet freedom.
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Technology against censorship: bridges and pluggable transports

You can use Tor to view websites that are censored or blocked. But what do you do when Tor itself is blocked? When it happens, you can use bridges and pluggable transports to get around the censors. Here is how to do it in Tor Browser:

Animated graphic showing 6 steps to configuring pluggable transports.

How does it work?

Censors block Tor in two ways: they can block connections to the IP addresses of known Tor relays, and they can analyze network traffic to find use of the Tor protocol. Bridges are secret Tor relays—they don't appear in any public list, so the censor doesn't know which addresses to block. Pluggable transports disguise the Tor protocol by making it look like something else—for example like HTTP or completely random.

There are several pluggable transports, and it can be hard to know which one to use. If it is your first time, try obfs4: it is a randomizing transport that works for most people. If obfs4 doesn't work, try fte. If that doesn't work, it may mean that the default bridges are blocked, and you should get a custom bridge from bridges.torproject.org. If the custom bridge doesn't work, try meek-azure or meek-amazon.

  • obfs4 is a randomizing transport: it adds an extra layer of specialized encryption between you and your bridge that makes Tor traffic look like random bytes. It also resists active-probing attacks, where the censor discovers bridges by trying to connect to them. obfs3 and scramblesuit are similar in nature to obfs4.
  • fte makes Tor traffic resemble plain HTTP. The name stands for "Format-Transforming Encryption."
  • meek makes Tor traffic look like a connection to an HTTPS website. Unlike the other transports, it doesn't connect directly to a bridge. meek first connects to a real HTTPS web server (in the Amazon cloud or the Microsoft Azure cloud) and from there connects to the actual bridge. Censors cannot easily block meek connections because the HTTPS servers also provide many other useful services.

There are a number of built-in, default bridges, which you can use just by choosing a pluggable transport name. For better secrecy, you should get custom bridges from bridges.torproject.org. meek doesn't need custom bridges; however it is slower and more expensive to operate than the other pluggable transports, so you should use obfs4 or fte if they work for you.

Tor is not the only project to use pluggable transports. We work often with researchers and developers to study Internet censorship, improve pluggable transports, and develop new ones. Psiphon and Lantern are two other projects that use pluggable transports. (Unlike Tor, they focus only on access and not on anonymity.)

If you are not censored yourself, you can help censored people by running a bridge with a pluggable transport. Running a bridge is the same as running a relay, just with a little extra configuration. See this guide: Become a PT bridge operator! Once your bridge is running, it will automatically become available to users at bridges.torproject.org.

The world of censorship is changing all the time. It's a good idea to learn how to use bridges and pluggable transports before you actually need them. Just last week, ISPs in Belarus began blocking public Tor relays—but bridges and pluggable transports are so far working to defeat the blocks. We are tracking other censorship events, such as those in Saudi Arabia, Kazakhstan, and elsewhere. If you know details of these or any other Tor blocks, please tell us. The best way to do that is to leave a comment on our bug tracker. (You can create an account first.)

Tor at the Heart: Tails

During the month of December, we're highlighting other organizations and projects that rely on Tor, build on Tor, or are accomplishing their missions better because Tor exists. Check out our blog each day to learn about our fellow travelers. And please support the Tor Project! We're at the heart of Internet freedom.
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Tails

Tails is a complete operating system designed to be used from a DVD, USB stick, or SD card independently of the computer's original operating system. It is free software and based on Debian GNU/Linux. Tails comes with several built-in applications pre-configured with security in mind: a web browser, an instant messaging client, an email client, an office suite, an image and sound editor, etc.

Tails aims at preserving privacy and anonymity online and allows users to:

  • Use the Internet anonymously to circumvent censorship; all connections to the Internet are forced to go through the Tor network. If an application tries to connect to the Internet directly, the connection is automatically blocked for security.
  • Leave no trace on the computer by default.
  • Use state-of-the-art cryptographic tools to encrypt files, emails and instant messaging.

Tails is configured with special care to not use the computer's hard-disks, even if there is some swap space on them. The only storage space used by Tails is in RAM, which is automatically erased when the computer shuts down. So you won't leave any trace on the computer either of the Tails system itself or what you used it for. This allows you to work with sensitive documents on any computer and protects you from data recovery after shutdown. Of course, you can still explicitly save specific documents to another USB stick or external hard-disk and take them away for future use.

Tails also comes with a selection of tools to protect your data using strong encryption:

  • Encrypt your USB sticks or external hard-disks using LUKS.
  • Automatically use HTTPS to encrypt all your communications to many major websites using HTTPS Everywhere.
  • Encrypt and sign your emails and documents using OpenPGP.
  • Protect your instant messaging conversations using OTR.
  • Securely delete your files and clean your diskspace using Nautilus Wipe.

Tails provides a secure platform that improves endpoint security by making it comparatively easier to use the right tools in the right way, protecting even less tech-savvy users from the most likely and highest impact risks.

Tor at the Heart: The OONI project

During the month of December, we're highlighting other organizations and projects that rely on Tor, build on Tor, or are accomplishing their missions better because Tor exists. Check out our blog each day to learn about our fellow travelers. And please support the Tor Project! We're at the heart of Internet freedom.
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In this post we provide an overview of OONI, a project under The Tor Project.

The Open Observatory of Network Interference (OONI) is a free software project under The Tor Project that aims to increase transparency about internet censorship around the world. To this end, OONI has developed multiple free software tests (called ooniprobe) that are designed to examine the following:

  • Blocking of websites;
  • Blocking of Instant Messaging software such as WhatsApp and Facebook Messenger;
  • Blocking of Tor, proxies, VPNs, and sensitive domains;
  • Detection of systems responsible for censorship, surveillance and traffic manipulation.

Anyone can run these tests to examine whether censorship is being implemented in their network. All data collected through ooniprobe is published and can serve as a resource for those who are interested in knowing how, when, and by whom internet censorship is being implemented. You can find OONI’s data in JSON format or via OONI Explorer: a global map for exploring and interacting with all the network measurement data that OONI has collected from 2012 to date.

Hundreds of volunteers have run ooniprobe across more than 100 countries around the world, shedding light on multiple instances of internet censorship. WhatsApp, for example, was found to be blocked in Brazil earlier this year, while Facebook and Twitter were censored during Uganda’s 2016 general elections. OONI data also shows that news websites were blocked in Iran and India, amongst many other countries, and that sites supporting LGBTI dating also appeared to be tampered with in Zambia.

OONI aims to equip the public around the world with data that can serve as evidence of internet censorship events. Such data not only shows whether a site or service was blocked, but more importantly, how it was blocked, when, where, and by whom. This type of information can be particularly useful to the following:

  • Lawyers: Examine the legality of the type of internet censorship implemented in your country, and use OONI’s data as evidence.
  • Journalists: Improve the credibility of your stories by referencing network measurement data as evidence of censorship events.
  • Researchers: Use OONI’s data to explore new questions. Researchers from the University of Cambridge and UC Berkeley, for example, were able to examine the differential treatment of anonymous users through the use of OONI data.
  • Activists, advocates, campaigners: Inform your work based on evidence of censorship events.
  • Circumvention tool projects: Inform the development of your tools and strategies based on OONI’s findings on censorship events around the world.

To empower participation in censorship research, OONI has established partnerships with local non-profit organizations around the world. Some of these organizations include:

These partnerships involve the daily collection of network measurements from local vantage points, determining which sites and services to test per country, and analyzing measurements within social, political, and legal context. Some partners, such as Sinar Project, even organize regional workshops to teach other groups and organizations how to measure internet censorship through the use of ooniprobe.

The Tor Project has supported the OONI project from day 1. Donate to The Tor Project today and help us continue to uncover internet censorship around the world.

Written by Maria Xynou, OONI’s Research and Partnerships Coordinator

Tor 0.2.8.11 is released, with small portability fixes

There's a new stable release of Tor!

Tor 0.2.8.11 backports fixes for additional portability issues that could prevent Tor from building correctly on OSX Sierra, or with OpenSSL 1.1. Affected users should upgrade; others can safely stay with 0.2.8.10.

You can download the source from the usual place on the website. Packages should be available over the next several days, including a TorBrowser release around December 14. Remember to check the signatures!

Below are the changes since 0.2.8.10.

Changes in version 0.2.8.11 - 2016-12-08

  • Minor bugfixes (portability):
    • Avoid compilation errors when building on OSX Sierra. Sierra began to support the getentropy() and clock_gettime() APIs, but created a few problems in doing so. Tor 0.2.9 has a more thorough set of workarounds; in 0.2.8, we are just using the /dev/urandom and mach monotonic time interfaces. Fixes bug 20865. Bugfix on 0.2.8.1-alpha.
  • Minor bugfixes (portability, backport from 0.2.9.5-alpha):
    • Fix compilation with OpenSSL 1.1 and less commonly-used CPU architectures. Closes ticket 20588.

Tor at the Heart: Library Freedom Project

During the month of December, we're highlighting other organizations and projects that rely on Tor, build on Tor, or are accomplishing their missions better because Tor exists. Check out our blog each day to learn about our fellow travelers. And please support the Tor Project! We're at the heart of Internet freedom.
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Library Freedom Project

Library Freedom Project is an initiative that aims to make real the promise of intellectual freedom in libraries by teaching librarians and their local communities about surveillance threats, privacy rights and responsibilities, and privacy-enhancing technologies to help safeguard digital freedoms.

Why libraries?

LFP focuses on libraries for several reasons: libraries are trusted community spaces and education centers, offering free computer classes and technology access -- quite often as the only such resource in their communities. Libraries serve people from all walks of life, including immigrants, poor and working people, and others who are under greater surveillance threats. Finally, libraries have a deep historical and ideological commitment to protecting privacy; for example, librarians in the United States were some of the earliest opponents of overbroad government surveillance programs like the USA PATRIOT Act. Library Freedom Project helps librarians turn that ideological commitment into procedural and technical reality by learning to teach privacy classes, operate infrastructure for privacy-enhancing technologies, and understand what to do when faced with information requests for patron data.

LFP + Tor

Tor is an essential part of Library Freedom Project. Through privacy trainings, LFP has taught thousands of librarians about using and teaching Tor in their libraries. Dozens of these libraries have even installed Tor Browser on public computers or have started operating Tor relays to help protect privacy at home and across the world. The relationship between LFP and the Tor Project is mutually beneficial; the Tor Project builds a tool that librarians saw the need for years ago, and librarians have helped perform much needed outreach and training on behalf of Tor. Thanks to the work of LFP, Tor is well-recognized by librarians and fairly mainstream in library culture. It is not uncommon for a library conference to offer talks about using Tor in libraries, and LFP's Tor Relays in Libraries project gave international attention to the role of libraries in the fight for privacy.

Support privacy training in your local community

By supporting Tor, you're helping bring privacy to local communities through the trusted space of the library. Donate to the Tor Project today, and then tell your librarian about Library Freedom Project.

Tor at the Heart: SecureDrop

During the month of December, we're highlighting other organizations and projects that rely on Tor, build on Tor, or are accomplishing their missions better because Tor exists. Check out our blog each day to learn about our fellow travelers. And please support the Tor Project! We're at the heart of Internet freedom.
Donate today!

SecureDrop

SecureDrop is an open-source whistleblower submission system that media organizations can install to accept documents from anonymous sources. It was originally coded by the late Aaron Swartz, with assistance from Wired editor Kevin Poulsen and James Dolan. The project was previously called DeadDrop. Freedom of the Press Foundation took over management of the project in October 2013. 

SecureDrop works by using two physical servers: a public-facing server that stores messages and documents, and a second server that performs security monitoring of the first. The code on the public-facing server is a Python web application that accepts messages and documents from the web and GPG-encrypts them for secure storage. This site is only made available as a Tor Hidden Service, which requires sources to use Tor, thus hiding their identity from both the SecureDrop server and many types of network attackers. Essentially, it’s a more secure alternative to the "contact us" form found on a typical news site. Every source who visits the site is given a unique "codename." The codename lets the source establish a relationship with the news organization without revealing his/her real identity or resorting to e-mail. They can enter the code name on a future visit to read any messages sent back from the journalist, or to submit additional documents and messages under the same persistent, but pseudonymous, identifier. The source is known by a different and unrelated code name on the journalist’s side. All of the source’s submissions, and replies to the source from journalists, are grouped together into a collection. Every time there’s a new submission by a source, their collection is bumped to the top of the submission queue. 

The SecureDrop application does not record your IP address, information about your browser, computer, or operating system. Furthermore, the SecureDrop pages do not embed third-party content or deliver persistent cookies to your browser. The server will only store the date and time of the newest message sent from each source. Once you send a new message, the time and date of your previous message is automatically deleted. Journalists are also encouraged to regularly delete all information from the SecureDrop server and store anything they would like saved in offline storage to minimize risk.

Over three dozen media organizations are currently using SecureDrop, including:

Tor at the Heart: Onion Browser (and more iOS Tor)

During the month of December, we're highlighting other organizations and projects that rely on Tor, build on Tor, or are accomplishing their missions better because Tor exists. Check out our blog each day to learn about our fellow travelers. And please support the Tor Project! We're at the heart of Internet freedom.
Donate today!

Onion Browser

Onion Browser is an open-source iOS web browser that connects to Tor. The app has been available in the Apple App Store since 2012; it was previously $0.99 but recently became free of charge. You can download it in the App Store here and access the source code on GitHub.

In addition to Tor support, Onion Browser features an experimental NoScript-like mode, user agent spoofing, and (since August) support for obfs4 and meek bridges.

It’s primarily developed by Mike Tigas, who works as a developer and investigative journalist at ProPublica by day. (Did you know? ProPublica is one of the first major news sites to be available via an onion sitepropub3r6espa33w.onion) The app is an independent community project and is supported by Patreon backers and other donors (read more about supporting Onion Browser here), with some key support also coming from the Guardian Project.

Onion Browser isn’t the prettiest app, lacking features like tabbed browsing, and it is starting to show it’s age a bit. But it still receives regular security updates and a new user interface is actively being developed (discussed in full below).

Challenges on iOS

Tor hasn't been well-represented on iOS over the years for a variety of reasons, mostly due to system peculiarities on the iOS platform. And although there’s a version of Firefox for iOS, several challenges prevent the interoperability that Tor developers are accustomed to on other platforms.

The most glaring restriction on iOS is that you're not allowed to fork subprocesses. Tor must be compiled into the app binary and hacked to run as a thread inside the app process to work on iOS. Among other things, this means that a system-wide Tor app, like Orbot on Android, is simply not possible on the platform. (At least, not yet: read about iCepa below!) And simply relying on another app’s Tor instance — as some tools do with Tor Browser Bundle — also doesn’t work on iOS, since all of an app’s functionality is halted soon after a user switches out of the app.

Even after solving the problem of just getting Tor to run, several other quirks prevent a lot of the functionality of Tor Browser (or even Orfox) from being easily reimplemented on iOS:

  • You're not allowed to implement your own browser engine and must use the WebKit framework built into the operating system. This separates Onion Browser from Tor Browser and Orfox, which are browsers based on Firefox Gecko. (On the other hand, this inadvertently made Onion Browser immune to the Firefox vulnerability targeting Tor Browser users last week.)
  • Only the older WebKit API (UIWebView) allows control over the SOCKS settings of the browser stack, so that we can configure it to use Tor. The newer framework (WKWebView) always uses your system proxy settings and can’t be reconfigured by an app at runtime. The APIs also contain vastly different functionality so that it's not always possible to convert code relying on one API to use the other. Firefox for iOS uses the newer WKWebView framework, which unfortunately means that much of the work on Firefox for iOS is quite difficult to use in a Tor-supporting iOS browser.
  • The WebKit APIs don’t allow a lot of control over the rendering and execution of web pages, making a Tor Browser-style security slider very difficult to implement. Many multimedia features on iOS also bypass the browser network stack — in particular, the iOS video player doesn’t use the same network stack as WebKit and therefore any browser action that launches the native video player may possibly leak traffic outside of Tor. Onion Browser tries to provide some functionality to block JavaScript and multimedia, but these features aren’t yet as robust as on other platforms.

iOS developments in the community

Despite the challenges, there are quite a few positive developments on the horizon — both around Onion Browser and the larger Tor iOS landscape.

Endless is an open source browser for iOS that uses the older UIWebView API and thus can be modified to support Tor. It adds a lot of important features over the existing Onion Browser, like a nicer user interface with tabbed browsing, HTTPS Everywhere, and HSTS Preloading. There’s a new version of Onion Browser in the works that’s based on Endless that will hopefully enter beta testing this month.

The NetworkExtension framework introduced in iOS 9 allows writing custom VPN software that the iOS system can use. A small coalition of Tor iOS developers are working on a tool called iCepa to use this framework to provide a Tor VPN to the entire phone — similar to the VPN mode of Orbot on Android. The framework was introduced with a tiny 5MB memory limit — which wasn’t enough to run both Tor and the controller app. But the memory limits have been increased to usable levels in iOS 10 and Conrad Kramer, the lead iCepa developer, has been making a bit of progress in recent months.

There’s also work ongoing work to make Tor easier to implement in other apps, like Tor.framework and CPAProxy. ChatSecure for iOS uses CPAProxy to power encrypted XMPP instant messaging over Tor, and the next version of Onion Browser uses Tor.framework rather than a custom solution. Onion Browser’s obfs4/meek support comes from another similar reusable framework called iObfs. Reusable pieces like this will hopefully encourage more developers to work on iOS software that supports Tor.

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