tag:theconversation.com,2011:/id/topics/tor-network-7451/articlesTor network – The Conversation2017-03-20T01:32:32Ztag:theconversation.com,2011:article/736412017-03-20T01:32:32Z2017-03-20T01:32:32ZTor upgrades to make anonymous publishing safer<figure><img src="https://images.theconversation.com/files/160793/original/image-20170314-10759-385iv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tor's improvements can help users stay private and anonymous online.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/anonymous-browsing-flat-illustration-concept-laptop-326161724">Anonymous online via shutterstock.com</a></span></figcaption></figure><p>In the coming months, the Seattle-based nonprofit <a href="https://www.torproject.org">The Tor Project</a> will be making some changes to improve how the Tor network protects users’ privacy and security. The free network lets users browse the internet anonymously. For example, using Tor can reduce the risk of being identified when dissidents speak out against their governments, whistleblowers communicate with journalists and victims of domestic abuse seek help.</p>
<p>In its most common, and best-known, function, a person using the free <a href="https://www.torproject.org/download/download-easy.html.en">Tor Browser</a> – essentially a privacy-enhanced version of Firefox – uses the internet mostly normally. Behind the scenes, the browser and the network handle the web traffic by bouncing the communications through a chain of three randomly chosen computers from all over the world, called “relays.” As of March 2017, the Tor network <a href="https://metrics.torproject.org/networksize.html?start=2016-12-13&end=2017-03-13">counts almost 7,000 of these relays</a>. The goal of leveraging these relays is to decouple a user’s identity from her activity.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/158813/original/image-20170228-13104-ylxylj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/158813/original/image-20170228-13104-ylxylj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=318&fit=crop&dpr=1 600w, https://images.theconversation.com/files/158813/original/image-20170228-13104-ylxylj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=318&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/158813/original/image-20170228-13104-ylxylj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=318&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/158813/original/image-20170228-13104-ylxylj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=400&fit=crop&dpr=1 754w, https://images.theconversation.com/files/158813/original/image-20170228-13104-ylxylj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=400&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/158813/original/image-20170228-13104-ylxylj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=400&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Tor bounces web traffic over three randomly selected Tor relays out of a total of around 7,000 relays.</span>
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<p>But those users are still, generally speaking, using others’ websites, which can be <a href="https://www.theatlantic.com/technology/archive/2016/02/the-research-pirates-of-the-dark-web/461829/">shut down</a> or <a href="http://www.bbc.com/news/technology-11928899">pressured into censoring online activity</a>. My own work as a scholar and volunteer member of The Tor Project also looks at the network’s way of allowing people to host websites privately and anonymously, which is where most of the upgrades to the system will come. </p>
<p>Called “onion services,” this element of the Tor network makes it possible for a person to run a website (or filesharing site, or chat service or even video calling system) from a dedicated server or even her own computer without exposing where in the world it is. That makes it much harder for authorities or opponents to take down. <a href="https://gitweb.torproject.org/torspec.git/tree/proposals/224-rend-spec-ng.txt">The upcoming changes</a> will fix flaws in the system’s original design, and employ modern-day cryptography to make the system future-proof. They will improve security and anonymity for existing Tor users and perhaps draw additional users who were concerned the prior protections were not enough when communicating and expressing themselves online.</p>
<h2>Understanding onion services</h2>
<p>As of March 2017, an estimated <a href="https://metrics.torproject.org/hidserv-dir-onions-seen.html?start=2016-12-15&end=2017-03-15">50,000 onion services</a> are operating on the Tor network. Onion services continuously come online and offline, though, so it is difficult to obtain exact numbers. Their name comes from the fact that, like Tor users, their identities and activities are protected by multiple layers of encryption, like those of an onion.</p>
<p>While <a href="https://doi.org/10.1109/ISI.2016.7745452">criminals are frequently early adopters</a> of anonymity
technology, as more people use the system, legal and ethical uses become far more common than illegal ones. Many onion services host websites, chat sites and video calling services. We don’t know all of what they’re doing because The Tor Project <a href="https://www.ipc.on.ca/wp-content/uploads/Resources/7foundationalprinciples.pdf">designs privacy into its technology</a>, so it does not and cannot keep track. In addition, when new onion services are set up, their very existence is private by default; an operator must choose to broadcast a service’s existence publicly.</p>
<p>Many owners do announce their sites’ existence, however, and the <a href="https://ahmia.fi">Ahmia search engine</a> provides a convenient way to find all publicly known onion services. They are as diverse as the internet itself, including a <a href="http://3g2upl4pq6kufc4m.onion">search engine</a>, a <a href="http://toristinkirir4xj.onion">literary journal</a> and an <a href="http://n3q7l52nfpm77vnf.onion">archive of Marxist and related writing</a>. <a href="https://facebookcorewwwi.onion">Facebook</a> even has a way for Tor users to <a href="https://www.facebook.com/notes/protect-the-graph/making-connections-to-facebook-more-secure/1526085754298237/">connect directly to its social media service</a>.</p>
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<a href="https://images.theconversation.com/files/158350/original/image-20170224-22978-rchc2h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/158350/original/image-20170224-22978-rchc2h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/158350/original/image-20170224-22978-rchc2h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=417&fit=crop&dpr=1 600w, https://images.theconversation.com/files/158350/original/image-20170224-22978-rchc2h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=417&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/158350/original/image-20170224-22978-rchc2h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=417&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/158350/original/image-20170224-22978-rchc2h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=524&fit=crop&dpr=1 754w, https://images.theconversation.com/files/158350/original/image-20170224-22978-rchc2h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=524&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/158350/original/image-20170224-22978-rchc2h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=524&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Facebook’s onion service, facebookcorewwwi.onion, when accessed through the Tor Browser.</span>
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<h2>Creating an onion site</h2>
<p>When a privacy-conscious user sets up an onion service (either <a href="https://www.torproject.org/docs/tor-manual.html.en">manually</a> or with a third-party tool such as <a href="https://onionshare.org">onionshare</a>), people who want to connect to it must use the Tor Browser or other Tor-enabled software; normal browsers such as Chrome and Firefox cannot connect to domains whose names end in “.onion.” (People who want to peek at onion sites without all of the network’s anonymity protections can visit <a href="https://tor2web.org">Tor2web</a>, which acts as a bridge between the open web and the Tor network.)</p>
<p>Originally, a new onion service was supposed to be known only to its creator, who could choose whether and how to tell others of its existence. Of course, some, like Facebook, want to spread the word as widely as possible. But not everyone wants to open their Tor site or service to the public, the way search and social media sites do.</p>
<p>However, a design flaw made it possible for an adversary to learn about the creation of a new onion service. This happened because each day, onion services announce their existence to several Tor relays. As happened in 2014, an <a href="https://motherboard.vice.com/en_us/article/carnegie-mellon-university-attacked-tor-was-subpoenaed-by-feds">attacker could potentially control enough relays</a> to keep track of new service registrations and slowly build up a list of onion sites – both secret and public – over time.</p>
<p>The same design flaw also made it possible for an attacker to predict what relays a particular service would contact the following day, allowing the adversary to become these very relays, and render the onion service unreachable. Not only could someone wanting to operate a private, secret onion service be unmasked under certain circumstances, but their site could effectively be taken offline.</p>
<p>The updates to the system <a href="https://gitweb.torproject.org/torspec.git/tree/proposals/250-commit-reveal-consensus.txt">fix both of these problems</a>. First, the relays each service contacts for its daily check-in will be randomly assigned. And second, the check-in message itself will be encrypted, so a relay can follow its instructions, but the human operator won’t be able to read it.</p>
<h2>Naming domains more securely</h2>
<p>Another form of security causes the names of onion services to be harder to remember. Onion domains are not named like regular websites are: <a href="http://www.facebook.com">facebook.com</a>, <a href="http://www.theconversation.com">theconversation.com</a> and so on. Instead, their names are derived from randomly generated cryptographic data, and often appear like <a href="http://expyuzz4wqqyqhjn.onion">expyuzz4wqqyqhjn.onion</a>, which is the website of The Tor Project. (It is possible to repeatedly generate onion domains until a user arrives at one that’s a bit easier to recognize. Facebook did that and – with a combination of luck and raw computational power – managed to create <a href="http://facebookcorewwwi.onion">facebookcorewwwi.onion</a>.)</p>
<p>Older onion services had names made up of 16 random characters. The new ones will use 56 characters, making their domain names look like this: l5satjgud6gucryazcyvyvhuxhr74u6ygigiuyixe3a6ysis67ororad.onion.</p>
<p>While the exact effects on users’ ability to enter onion services’ addresses haven’t been studied, lengthening their names shouldn’t affect things much. Because onion domain names have always been hard to remember, most users take advantage of the Tor Browser’s bookmarks, or copy and paste domain names into address fields.</p>
<h2>Protecting onion sites</h2>
<p>All this new design makes it significantly harder to discover an onion service whose operator wants it to remain hidden. But what if an adversary still manages to find out about it? The Tor Project has solved that problem by allowing onion services to challenge would-be users to enter a password before using it.</p>
<p>In addition, The Tor Project is updating the cryptography that onion services employ. Older versions of Tor used a <a href="https://people.csail.mit.edu/rivest/Rsapaper.pdf">cryptosystem called RSA</a>, which could be broken by calculating the two prime factors of very large numbers. While RSA is not considered insecure yet, researchers have devised <a href="http://www.ams.org/notices/199902/boneh.pdf">several attacks</a>, so The Tor Project is replacing it with what is called <a href="https://blog.cloudflare.com/a-relatively-easy-to-understand-primer-on-elliptic-curve-cryptography/">elliptic-curve cryptography</a>, which uses keys that are shorter, more efficient and understood to be at least as secure.</p>
<p>The developers are also updating other basic elements of the encryption standards used in Tor. The hash function, which Tor uses to derive short and constant-length text strings from arbitrarily long data, will change from the troubled – and <a href="https://shattered.io/">partially broken</a> – SHA-1 to the modern <a href="https://www.nist.gov/news-events/news/2015/08/nist-releases-sha-3-cryptographic-hash-standard">SHA-3</a>. In addition, secret keys for the <a href="https://doi.org/10.6028/NIST.FIPS.197">Advanced Encryption Standard</a> cryptosystem will be twice as long as before – and therefore significantly harder to break. These don’t address specific immediate threats, but protect against future improvements in attacking encryption.</p>
<p>With these improvements to the software that runs Tor, we’re expecting to be able to prevent future attacks and protect Tor users around the world. However, better anonymity is only one aspect in the bigger picture. More experimentation and research are necessary to make onion services easier to use.</p><img src="https://counter.theconversation.com/content/73641/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Philipp Winter is a member of The Tor Project.</span></em></p>The Tor Project is upgrading its protections for internet users’ privacy and anonymity. A scholar and volunteer member of the nonprofit effort explains what’s changing and why.Philipp Winter, Postdoctoral Research Associate in Computer Science, Princeton UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/426592015-06-02T15:02:31Z2015-06-02T15:02:31ZThe fall of Silk Road isn’t the end for anonymous marketplaces, Tor or bitcoin<figure><img src="https://images.theconversation.com/files/83700/original/image-20150602-19232-ilns3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Silk Road, gone but not forgotten.</span> <span class="attribution"><a class="source" href="http://commons.wikimedia.org/wiki/File:Silk_Road_Seized.jpg">FBI</a></span></figcaption></figure><p>Ross Ulbricht, aka the “Dread Pirate Roberts”, has been sentenced to life in prison without parole by a Manhattan Federal Court for masterminding the Silk Road anonymous online illegal marketplace. Ulbricht was labelled a <a href="http://www.fbi.gov/newyork/press-releases/2015/ross-ulbricht-aka-dread-pirate-roberts-sentenced-in-manhattan-federal-court-to-life-in-prison">drug dealer and criminal profiteer</a>, and Judge Forrest was unequivocal in stating that “a message must be sent out that no one is above the law”.</p>
<p>The Silk Road was an online marketplace designed to allow users to conduct illegal business anonymously beyond the reach of law enforcement. It operated like an eBay for illegal goods, complete with the opportunity for buyers to provide feedback scores to sellers so others could gauge their trustworthiness and quality of product.</p>
<p>The site used a mix of sophisticated privacy technologies to try to hide the identities of its users. Run as a <a href="https://www.torproject.org/about/overview.html.en">Tor</a> hidden service within the Dark Web, Silk Road’s servers were only accessible through Tor software in order to mask their IP addresses and physical location. Transactions were carried out using <a href="https://bitcoin.org/en/faq">bitcoin</a> due to the pseudonymity it affords. Buyers and sellers guides were available on the website to assist in using the technology without detection.</p>
<p>Officially the FBI insists that Ulbricht made mistakes which allowed <a href="http://www.v3.co.uk/v3-uk/news/2363958/fbi-used-leaky-captcha-to-catch-silk-roads-hidden-web-servers">detectives to uncover his identity and location</a>. The subsequent sites that attempted to follow in its wake were brought down through <a href="http://www.justice.gov/sites/default/files/usao-sdny/legacy/2015/03/25/Benthall%2C%20Blake%20Complaint.pdf">similar mistakes</a>. But the evidence and explanations given by the FBI in court were not convincing, leading to rumours that the FBI <a href="http://phys.org/news/2015-02-tor-silk-road.html">used malware or enlisted the NSA</a> to help track down Silk Road and its users within Tor. </p>
<h2>Technological fall-out</h2>
<p>It is already known that Tor <a href="http://www.theguardian.com/world/2013/oct/04/tor-attacks-nsa-users-online-anonymity">users are vulnerable</a> at the point that traffic enters and exits the Tor network. Generally though it is thought that <a href="https://theconversation.com/tor-the-last-bastion-of-online-anonymity-but-is-it-still-secure-after-silk-road-35395">users cannot be tracked within the network</a> – but if there is some basis to the speculation that the FBI used malware or enlisted the help of the NSA to bring down the Silk Road then it may be possible that to identify the real internet IP addresses associated with Tor traffic. Certainly this would put an end to any chances of a new Silk Road, and it would also inevitably lead to prosecution of much of the other illegal activity that goes on within the Deep Web. On the other hand, the lack of moves by law enforcement suggests this may not be the case.</p>
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<img alt="" src="https://images.theconversation.com/files/83703/original/image-20150602-19249-185dqzb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/83703/original/image-20150602-19249-185dqzb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/83703/original/image-20150602-19249-185dqzb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/83703/original/image-20150602-19249-185dqzb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/83703/original/image-20150602-19249-185dqzb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/83703/original/image-20150602-19249-185dqzb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/83703/original/image-20150602-19249-185dqzb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">You have to go far to find somewhere that accepts bitcoin.</span>
<span class="attribution"><a class="source" href="http://commons.wikimedia.org/wiki/File:De_Waag_Bitcoin.jpg">Targaryen</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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</figure>
<p>The limits to the anonymity afforded by bitcoin has also been highlighted. While the value of bitcoins remains within the blockchain, the anonymity persists. But for the owner of bitcoins to realise their value, they must be spent or transferred through exchanges into real-world currency – at which point the owner is liable to be traced. Once a <a href="https://bitcoin.org/en/choose-your-wallet">wallet ID</a> has been linked to an individual bitcoin, transactions become highly traceable, as all transactions involving that ID are viewable on the public ledger. This is why governments are choosing to <a href="https://theconversation.com/governments-want-to-regulate-bitcoin-is-that-even-possible-39266">regulate to bitcoin through digital exchanges</a>.</p>
<p>Unless bitcoin becomes more readily accepted then it will be hard for criminals to avoid the temptation to cash out at digital exchanges, linking them to their ill-gotten gains. However, there may be other cryptocurrencies with the means to get around these weaknesses in the future.</p>
<p>So while the Silk Road and several of its immediate successors are gone, the suggestion that the technology behind these marketplaces is flawed is based on speculation that the FBI or NSA have cracked them. If the FBI’s claims that Ulbricht and <a href="http://www.fbi.gov/newyork/press-releases/2014/operator-of-silk-road-2.0-website-charged-in-manhattan-federal-court">Blake Benthall</a> of “Silk Road 2.0” were caught due to their own mistakes are true, then it’s still possible for similar anonymous marketplaces to escape prosecution in the future. </p>
<p>Of course, in light of the severe sentence handed to Ulbricht it will depend on whether those would-be entrepreneurs with plans to found other online marketplaces have sufficient belief in the technology’s security to try their luck. So perhaps the judge’s aim in sentencing to deter others could still play a part.</p><img src="https://counter.theconversation.com/content/42659/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Shillito does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The technology behind Silk Road is still sound, but with the potential for a life sentence it would take faith to deploy them.Matthew Shillito, PhD student, University of LiverpoolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/353952015-02-05T16:58:55Z2015-02-05T16:58:55ZTor: the last bastion of online anonymity, but is it still secure after Silk Road?<figure><img src="https://images.theconversation.com/files/71223/original/image-20150205-28608-mlau0q.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tor, your online an-onionising software.</span> <span class="attribution"><a class="source" href="http://commons.wikimedia.org/wiki/File:Tor_project_logo_hq.png">Tor Project</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>The Silk Road trial has concluded, with Ross Ulbricht <a href="http://www.wsj.com/articles/silk-road-creator-found-guilty-of-cybercrimes-1423083107">found guilty</a> of running the anonymous online marketplace for illegal goods. But questions remain over how the FBI found its way through Tor, the software that allows anonymous, untraceable use of the web, to gather the evidence against him.</p>
<p>The development of anonymising software such as Tor and Bitcoin has forced law enforcement to develop the expertise needed to identify those using them. But if anything, <a href="http://www.dailydot.com/crime/silk-road-ross-ulbricht-evidence-list/">what we know about the FBI’s case</a> suggests it was tip-offs, <a href="http://www.forbes.com/sites/sarahjeong/2015/01/14/the-dhs-agent-who-infiltrated-silk-road-to-take-down-its-kingpin/">inside men</a>, <a href="http://arstechnica.com/tech-policy/2015/01/friend-who-helped-ulbricht-build-silk-road-testifies-against-him/">confessions</a>, and Ulbricht’s own errors that were responsible for his conviction.</p>
<p>This is the main problem with these systems: breaking or circumventing anonymity software is hard, but it’s easy to build up evidence against an individual once you can target surveillance, and wait for them to slip up. </p>
<h2>The problem</h2>
<p>A design decision in the early days of the internet led to a problem: every message sent is tagged with the numerical Internet Protocol (IP) addresses that identify the source and destination computers. The network address indicates how and where to route the message, but there is no equivalent indicating the identity of the sender or intended recipient. </p>
<p>This conflation of addressing and identity is bad for privacy. Any internet traffic you send or receive will have your IP address attached to it. Typically a computer will only have one public IP address at a time, which means your online activity can be linked together using that address. Whether you like it or not, marketers, criminals or investigators use this sort of profiling without consent all the time. The way IP addresses are allocated is geographically and on a per-organisation basis, so it’s even possible to pinpoint a surprisingly accurate location.</p>
<p>This conflation of addressing and identity is also bad for security. The routing protocols which establish the best route between two points on the internet are not secure, and have been <a href="http://arstechnica.com/security/2013/11/repeated-attacks-hijack-huge-chunks-of-internet-traffic-researchers-warn/">exploited by attackers</a> to take control of (hijack) IP addresses they don’t legitimately own. Such attackers then have access to network traffic destined for the hijacked IP addresses, and also to anything the legitimate owner of the IP addresses should have access to.</p>
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<p>This is why those looking for cat videos on YouTube on February 24, 2008 <a href="http://www.wired.com/2008/02/pakistans-accid/">found themselves at Pakistan Telecom instead</a>, why hackers made off with US$83,000 worth of bitcoin between February and May 2014 by impersonating the legitimate owners, and why hundreds of organisations found their communications <a href="http://arstechnica.com/security/2013/11/repeated-attacks-hijack-huge-chunks-of-internet-traffic-researchers-warn/">mysteriously routed via computers in Belarus and Iceland</a> in 2013.</p>
<h2>Redesigning with security in mind</h2>
<p>Onion routing was developed to correct these mistakes, separating identity and address so that it’s possible to communicate through the internet without revealing the IP address used. Originally a <a href="http://www.onion-router.net/">US Navy Research Laboratory project</a>, the latest implementation of onion routing is known as <a href="https://www.torproject.org/">Tor</a> and is independently developed by the non-profit Tor Project.</p>
<p>Tor routes internet traffic through three or more intermediate computers called nodes, which prevents anyone listening in – and any website the traffic connects to – from knowing the source of the traffic or working out who is communicating with whom. Even Tor nodes aren’t individually aware of the details of which user, where, is connecting to what. The first node sees the user’s IP address, the last knows which site is being accessed, but unless both the first and last nodes are controlled maliciously these two facts won’t be linked.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/71202/original/image-20150205-28618-1pf3ee.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/71202/original/image-20150205-28618-1pf3ee.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=384&fit=crop&dpr=1 600w, https://images.theconversation.com/files/71202/original/image-20150205-28618-1pf3ee.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=384&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/71202/original/image-20150205-28618-1pf3ee.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=384&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/71202/original/image-20150205-28618-1pf3ee.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=482&fit=crop&dpr=1 754w, https://images.theconversation.com/files/71202/original/image-20150205-28618-1pf3ee.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=482&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/71202/original/image-20150205-28618-1pf3ee.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=482&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">How Tor works.</span>
<span class="attribution"><a class="source" href="https://privacycanada.net">Privacy Canada/EFF</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Who uses Tor?</h2>
<p>There are all sorts of reasons to use Tor to protect privacy: law enforcement monitoring criminals, firms studying potential takeover targets, those who don’t like advertisers profiling them, or political activists in authoritarian states. An increasing number use Tor to access websites that are blocked in their country, as Tor’s anonymisation prevents the censor’s software from detecting the traffic is destined for a banned website.</p>
<p>As well as websites on the everyday internet, Tor allows the creation of <a href="https://www.torproject.org/docs/hidden-services.html.en">hidden services</a>: websites accessed only through the Tor network, of which the Silk Road is an example. This ensures privacy and security by identifying sites not with an IP address and domain name but with a cryptographic key. Without this key, there’s no way for a would-be eavesdropper to impersonate the real website and intercept traffic directed to it. These are represented by a URL ending in .onion – accessed with a Tor-enabled browser, Facebook is at <a href="http://www.theguardian.com/technology/2014/oct/31/facebook-anonymous-tor-users-onion">facebookcorewwwi.onion</a>.</p>
<h2>An evolving architecture</h2>
<p>Tor isn’t perfect. It can’t protect traffic that has left the Tor network, for example, where traffic becomes vulnerable to all the usual attacks. The solution to this is end-to-end encryption – preventing monitoring or tampering not only for Tor users but for everyone else on the internet too. </p>
<p>Another potential weakness is flaws in other software used with Tor. The <a href="http://www.wired.com/2013/09/freedom-hosting-fbi/">FBI distributed malware</a> to every visitor to a group of hidden services, some of which claimed to distribute child abuse images. The malware exploited a vulnerability in the Firefox web browser in order to send the real IP address of the user and other identifying information back to the FBI.</p>
<p>It’s been suggested that a flaw in the software behind the Silk Road gave the FBI the breakthrough that let them discover the IP address and so the real location of the Silk Road’s servers. But the lack of detail on this from the FBI, compared to the other evidence gleaned from Ulbricht’s server and laptop computer, has <a href="http://www.wired.com/2014/09/fbi-silk-road-hacking-question/">led some to ask</a> whether the FBI used techniques it doesn’t want openly discussed – such as the involvement of the National Security Agency and its vast surveillance infrastructure.</p>
<p>It could also have been what’s called a <a href="https://blog.torproject.org/blog/tor-security-advisory-relay-early-traffic-confirmation-attack">traffic confirmation attack</a>, where the entry and exit Tor nodes <a href="http://arstechnica.com/security/2014/11/law-enforcement-seized-tor-nodes-and-may-have-run-some-of-its-own/">are compromised</a> or monitored. Our own research has shown that this can <a href="http://www.cs.ucl.ac.uk/staff/s.murdoch/papers/pet07ixanalysis.pdf">allow communications to be de-anonymised</a>, and researchers including myself are working on how to address this – by making it difficult or unlikely for any one person to control the entry and exit nodes, and by reducing the potential damage if this occurs.</p>
<p>The internet has come a long way since its beginnings, and simplifications and rationalisations made for good reasons at the time need to be re-visited in light of what’s been learned in the 40 years since. </p>
<p>Conflating addressing and identity is one of these decisions. Tor – useful in its own right – also indicates how the internet’s architecture should provide strong assurance of identity when needed, and strong privacy when not. Given enough resources, attackers will be able to de-anonymise at least some of Tor’s users, some of the time, but it’s still the best web privacy solution we have today. The next generation of systems will be better still.</p><img src="https://counter.theconversation.com/content/35395/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steven J. Murdoch is member of The Tor Project.</span></em></p>The Silk Road trial has concluded, with Ross Ulbricht found guilty of running the anonymous online marketplace for illegal goods. But questions remain over how the FBI found its way through Tor, the software…Steven J. Murdoch, Royal Society University Research Fellow, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/300632014-08-07T09:26:01Z2014-08-07T09:26:01ZNSA surveillance is a clear threat to journalism in America<p>Digital mass surveillance is having a chilling effect on US democracy, affecting journalists and lawyers, a <a href="http://www.hrw.org/node/127364">report</a> from human rights organisations has warned.</p>
<p>The report, by Human Rights Watch and the <a href="https://www.aclu.org/">American Civil Liberties Union</a>, concludes that some of the most fundamental freedoms are under threat. The organisations argue that the government’s policies on secrecy and preventing leaks, as well as its stance on officials talking to the media, undermine traditional US values.</p>
<h2>Press under threat</h2>
<p>When it comes to journalism, the Snowden case has already had an impact in a number of high-profile cases. In July 2013, staff at the Guardian had to destroy hard drives containing files leaked by Snowden under threat of action from the UK government. In February of the same year, <a href="http://www.bbc.co.uk/news/uk-23782782">David Miranda</a>, partner of former Guardian journalist Glenn Greenwald, was held at a London airport for nine hours under the UK Terrorism Act, because of Greenwald’s association with the Snowden case.</p>
<p>These concerns do indeed appear to be playing out in the industry. In 2012 alone, the US federal government reclassified 95 million pieces of information. It’s not clear how many of these were made more or less secret but overclassification is becoming a concern. It has been <a href="http://www.nytimes.com/2011/11/07/opinion/national-security-and-americas-unnecessary-secrets.html">estimated</a> that between 50% and 90% of classified documents could be made public without them posing a security threat.</p>
<p>The Obama administration has also used the 1917 Espionage Act to routinely target whistleblowers. Under the current presidency, eight people have been pursued for leaking information to the press, including Edward Snowden and Chelsea Manning, the WikiLeaks source. Just three such prosecutions were pursued between 1917 and Obama’s election. </p>
<p>“We’re not able to do our jobs if sources are in danger”, a national security reporter told Human Rights Watch and the ACLU. These concerns are in turn leading to increasing use of encryption technology among a significant number of journalists interviewed for the report.</p>
<p>But while the use of some tools such as the Tor browser or the PGP encryption service to secure emails can definitely reduce the risk of being exposed to government surveillance, the report notes that many journalists fear they are not completely safe. This was a fear raised by Pulitzer Prize-winning reporter Erich Schmitt when he warned that asking sources to protect their digital communication can actually attract more attention to their communications. Others reported having to pay for encryption technologies out of their own pocket and while some journalists are being trained to use them by their employers, others are having to do it alone.</p>
<p>These difficulties are also affecting public discourse, especially in the United States. If sources are reluctant to talk, information doesn’t get through to the public. When it comes to reporting national security issues, several journalists described the climate in the US as comparable to what they might come up against in more authoritarian countries. Journalist Peter Maass is quoted in the report as saying he is “horrified and outraged” by the situation, revealing that he has the same problems working as a reporter in the US as he did in the former Soviet Union and North Korea.</p>
<p>Similar concerns are expressed in the report by lawyers, who warn that client confidentiality is at risk. “I don’t send any information by email, attachment, or phone”, says one interviewed defense attorney, “I don’t use GChat or WhatsApp for anything but ‘Hi, what’s up?’. I don’t even talk on Skype.” By contrast, the government officials interviewed for the report backed NSA surveillance.</p>
<p>In October 2013, the Committee to Protect Journalism released a report denouncing the dangers which journalism is exposed to in the US in the wake of the Snowden case, coming to similar conclusions as the two human rights organisations. And it came to no surprise for some to see the NSA listed in the 2014 Reporters Without Borders <a href="http://12mars.rsf.org/2014-en/enemies-of-the-internet-2014-entities-at-the-heart-of-censorship-and-surveillance/">Enemies of the Internet</a> report. </p>
<p>This report is not the first to raise concerns about the future implications of what we have learned from the Snowden leaks but it gives us a broader picture of the magnitude of the case. Snowden himself has accused the NSA of <a href="https://theconversation.com/the-internet-is-on-fire-but-snowdens-heroes-cant-save-us-24241">setting fire to the future of the internet</a> but now it seems journalism and the legal profession are in danger too.</p>
<p>In fact, the Snowden case implicates every field of our constantly connected and wired society, especially when it comes to <a href="https://theconversation.com/nine-reasons-you-should-care-about-nsas-prism-surveillance-15075">digital communication through commercial and popular tools and social media</a>. We should be outraged but we should also use the case as evidence in the fight to narrow the scope of surveillance, reduce government secrecy and better protect national security whistleblowers – as well as the lawyers who defend them and the journalists who tell their stories.</p><img src="https://counter.theconversation.com/content/30063/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Philip Di Salvo does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Digital mass surveillance is having a chilling effect on US democracy, affecting journalists and lawyers, a report from human rights organisations has warned. The report, by Human Rights Watch and the…Philip Di Salvo, PhD Candidate in Communications Sciences and Journalism, Università della Svizzera italianaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/216682013-12-20T15:25:59Z2013-12-20T15:25:59ZAnonymity will be the next victim of internet censorship<figure><img src="https://images.theconversation.com/files/38375/original/y9fg7k8h-1387551032.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The dark web is under threat.</span> <span class="attribution"><span class="source">Fir0002</span></span></figcaption></figure><p>The worrying developments in UK internet freedom over the last year make predictions for 2014 gloomy to say the least. Censorship now affects us all, so we should be thinking about it. And it’s not politically driven censorship we should be most afraid of.</p>
<p>This year has been characterised by tension between the UK government’s use of terrorism laws and free speech and, more recently, by <a href="http://www.bbc.co.uk/news/uk-25430582">concern</a> over the <a href="http://mccullagh.org/misc/articles/cwd.keys.to.the.kingdcom.1996.txt">unavoidable over-blocking</a> of content in the name of protection. Yet there are greater threats to our internet freedom than the heavy hand of the government.</p>
<h2>Oversight versus interference</h2>
<p>Both the government and internet service providers have abdicated responsibility for the quality control of the security filters being put in place in a bid to prevent children from accessing pornographic content at home.</p>
<p>ISPs such as <a href="https://www.openrightsgroup.org/blog/2013/bt-filters-reply">BT</a> and <a href="https://www.openrightsgroup.org/blog/2013/skys-reply-to-org-on-default-internet-filters">Sky</a> have delegated the task of deciding what to block to third party companies. For <a href="http://politics.co.uk/comment-analysis/2013/12/19/comment-three-embarrassing-truths-about-david-cameron-s-porn">accountability</a> and <a href="https://www.openrightsgroup.org/blog/2013/ukccis-overblocking">oversight</a> that is bad news but in terms of possible political interference it is actually good.</p>
<h2>Why censorship?</h2>
<p>There have been three main drivers for internet censorship. One is child abuse imagery, the banning of which is in line with the general population’s views. Websites containing child porn can be taken down, for example through the Internet Watch Foundation, and, since November, <a href="https://theconversation.com/blocks-just-move-child-porn-under-the-counter-20531">search engines have returned warnings and reduced results</a> when certain terms have been searched for. Although porn in general is not illegal, the ISPs’ filters will have an impact on the blocking of child abuse by negatively affecting the distribution of borderline illegal material. </p>
<p>The second driver is combating extremism. It is still unclear how censorship will be applied here, but <a href="https://theconversation.com/blocking-extremist-sites-is-not-the-same-as-fighting-child-porn-20930">classification is highly problematic</a>. No clear public mandate exists for this censorship, nor are links with legislation on issues such as hate speech or proscription of organisations, made explicit. In <a href="http://bt.custhelp.com/app/answers/detail/a_id/46768/kw/parental%20filter/c/346,6679,6680#settingup">its filters</a>, BT does not have an “extremism” category, although some content may fall within its “weapons and violence” or “hate” labels.</p>
<p>The final category is media organisations aiming to protect their copyright. The <a href="http://www.legislation.gov.uk/ukpga/2010/24/contents">2010 Digital Economy Act</a> allows for ISPs to apply sanctions (such as bandwidth restriction and disconnection) to users who have downloaded copyrighted material. ISPs have also been forced to block file sharing websites, such as <a href="http://www.bbc.co.uk/news/technology-17894176">The Pirate Bay</a> and BT includes the practice in its filtering. But file sharing isn’t always illegal and even when it is, public opinion is divided about whether or not it is acceptable. The heavy-handed measures that can be taken show the impact of the commercial interests in this domain.</p>
<h2>Mission creep</h2>
<p>It’s important to note that <a href="http://bt.custhelp.com/app/answers/detail/a_id/46768/kw/parental%20filter/c/346,6679,6680#settingup">BT is filtering in 14 categories</a>, even though David Cameron promised nothing broader than “porn” filters. The generous explanation for this is that the third party providers being used by ISPs already had a range of filtering options in place for parental controls or use in schools, for example filtering against high bandwidth activities like file sharing and media streaming.</p>
<p>More worryingly though, it <a href="http://www.theregister.co.uk/2013/12/17/bt_parental_controls_will_block_proxies_and_anonymiser_sites/">has been reported</a>
that the BT filters also restrict access to sites promoting the use of proxies. This is where the next battle over internet censorship will be fought. Restricting the technological means through which internet users can obscure their IP addresses, obtain some anonymity, and hide the content they are accessing from others is the next big target.</p>
<p>Again, the excuse may be that the third party providers already have this built into their products for good reasons. In the context of school web filters, for example, circumvention of filters needs to be prevented. </p>
<p>But it looks like these measures could well be broadened. The IWF and the Child Exploitation and Online Protection Centre have been<br>
<a href="http://www.theguardian.com/technology/2013/nov/18/online-child-abuse-peer-to-peer">asked to investigate child abuse imagery in the “Dark Web”</a>. The only predictable, and sensible, recommendation for reducing child porn to come out of this will be to restrict access to the Dark Web. And that has to be done by restricting a user’s ability to disguise their activities. </p>
<h2>Media companies and the TTIP</h2>
<p>This by itself will not cause the UK government to restrict access to Tor, VPNs, or proxies in general. However, the media copyright lobby will want to make this happen because peer-to-peer networks, content indexed through torrent sites, possibly using some form of anonymous routing along the way, carry the majority of the “illegal” file sharing load.</p>
<p>Media companies stand to gain significant powers, possibly trumping national legislation, through trade agreements such as <a href="http://www.techdirt.com/articles/20131219/05544825628/actas-back-european-commission-reveals-plans-to-put-corporate-christmas-list-ip-demands-into-taftattip.shtml">TTIP</a>. Using these, they will want to close off all avenues of illegal file sharing, and they are unlikely to care about collateral damage to internet privacy. Thus, we have to worry about restrictions on the use of Tor anonymous routing, VPNs, proxies, and any other ways that allow us to be more anonymous and protected on the internet.</p>
<p>This prediction then brings together the two big internet freedom storylines of the last six months. The government’s desire for quick internet censorship solutions will end up impeding our capacity to defend ourselves against overzealous surveillance from intelligence services and tech companies.</p>
<h2>The Tor fightback</h2>
<p>The good news is that Tor traffic has <a href="http://www.youtube.com/watch?v=GwMr8Xl7JMQ">proved hard to detect and shut down</a>. Many countries have tried and failed. Security companies claiming to have the required technology typically are only able to block older versions.</p>
<p>These days, Tor connections look like normal secure web traffic. Currently only China systematically and openly blocks Tor (with its Great Firewall) for long periods of time. They do this by blocking the eight “directory authorities” that form the entry point to Tor, in combination with Deep Packet Inspection. In response, the Tor project continually develops new camouflage methods, and also <a href="https://ooni.torproject.org/">very promising tools for detecting internet censorship</a>. It is very sad that we may be using this tool sometime soon in the UK, and that Russia and Japan have been reported to be considering blocking Tor. All is not lost, but we should be on our guard.</p><img src="https://counter.theconversation.com/content/21668/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eerke Boiten is a senior lecturer in the School of Computing at the University of Kent, and Director of the University's interdisciplinary Centre for Cyber Security Research. He receives funding from EPSRC for the CryptoForma Network of Excellence on Cryptography and Formal Methods. </span></em></p><p class="fine-print"><em><span>Julio Hernandez-Castro does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The worrying developments in UK internet freedom over the last year make predictions for 2014 gloomy to say the least. Censorship now affects us all, so we should be thinking about it. And it’s not politically…Eerke Boiten, Senior Lecturer, School of Computing and Director of Interdisciplinary Cyber Security Centre, University of KentLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/189452013-10-07T04:41:59Z2013-10-07T04:41:59ZSorry NSA, but the Tor network is secure – and it’s here to stay<figure><img src="https://images.theconversation.com/files/32543/original/dgm2m4zf-1381114888.jpg?ixlib=rb-1.1.0&rect=384%2C0%2C637%2C410&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There are still places to hide online.</span> <span class="attribution"><span class="source">nataliej/Flickr</span></span></figcaption></figure><p>You may have seen <a href="http://www.theguardian.com/world/2013/oct/04/nsa-gchq-attack-tor-network-encryption">reports</a> over the weekend about yet another instalment of the US National Security Agency’s (<a href="http://www.nsa.gov/">NSA</a>) surveillance system - this time a <a href="http://www.theguardian.com/world/interactive/2013/oct/04/tor-stinks-nsa-presentation-document">set of slides</a> focused on cracking the <a href="https://www.torproject.org/">Tor network</a>, a popular method of staying anonymous online.</p>
<p>Developed at different stages with financing from the US military’s Defence Advanced Research Projects Agency (<a href="http://www.darpa.mil/">DARPA</a>) and the Electronic Frontier Foundation (<a href="https://www.eff.org/">EFF</a>), Tor is a network of mutual anonymity. </p>
<p>But now it seems even this seemingly uncrackable network is under some degree of surveillance by the NSA and its <a href="http://apps.washingtonpost.com/g/page/world/gchq-report-on-mullenize-program-to-stain-anonymous-electronic-traffic/502/">British counterpart</a>, the Government Communications Headquarters (<a href="http://www.gchq.gov.uk/Pages/homepage.aspx">GCHQ</a>).</p>
<p>So how much surveillance, exactly?</p>
<h2>You’re always being watched</h2>
<p>Many companies track your patterns of movement online. You can be sure Facebook, Twitter, Google, and YouTube are doing their best to make money from your online activities. </p>
<p>Former NSA employee <a href="http://en.wikipedia.org/wiki/Edward_Snowden">Edward Snowden</a> recently revealed some of the operations of the US security apparatus, and the extent of their data capture is – to put it mildly – frightening.</p>
<p>It’s frightening because none of us can effectively do anything about being automatically captured by the covert surveillance of NSA’s <a href="https://theconversation.com/prism-schism-the-nsa-leaks-reveal-a-broken-system-15099">PRISM</a> infrastructure. If you are electronically within three degrees of separation from anyone who has travelled through the US, then you’re under assessment. </p>
<p>Thanks to journalists such as <a href="http://www.theguardian.com/profile/glenn-greenwald">Glenn Greenwald</a>, the details of the NSA are fast becoming a matter of public record. Events like 9/11 and the <a href="https://theconversation.com/topics/boston-marathon-bombing">Boston Marathon bombings</a> mean that, for some, the NSA’s operations are a perfectly appropriate and necessary part of the modern state. </p>
<p>But other users - assuming something similar to the NSA was already in operation - have developed networks like Tor to protect against surveillance.</p>
<h2>Tor: total anonymity?</h2>
<p>Tor was designed, apparently, to protect communication between political dissidents, and to allow everyday users to avoid location-based snooping. </p>
<p>It is because of Tor that you are aware of the death tolls and atrocities in the wars in Iraq and Afghanistan; it is through Tor that civilian video in Syria gets uploaded to <a href="http://www.liveleak.com/">LiveLeak</a>. Tor is used by hackers in Mexico to combat drug cartels.</p>
<p>It has also been put towards all sorts of illegal activity – online criminal syndicates, child pornography, terrorism networks, drug cartels (notably the now-defunct <a href="https://theconversation.com/end-of-the-silk-road-how-did-dread-pirate-roberts-get-busted-18886">Silk Road</a>), and even the shady end of police departments are accessible through Tor. </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/32545/original/w9qpcvgx-1381115144.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/32545/original/w9qpcvgx-1381115144.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/32545/original/w9qpcvgx-1381115144.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/32545/original/w9qpcvgx-1381115144.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/32545/original/w9qpcvgx-1381115144.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/32545/original/w9qpcvgx-1381115144.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/32545/original/w9qpcvgx-1381115144.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Regular users aren’t very good at keeping things secret.</span>
<span class="attribution"><span class="source">ceridwen/Flickr</span></span>
</figcaption>
</figure>
<p>Tor is such an effective anonymisation device for criminals that it makes the surveillance of regular individuals through Facebook and Google largely ridiculous.</p>
<p>Tor operates by transferring data between members using many layers of encryption to hide the contents. The encrypted data is sent along a randomly determined path. Each computer along the path unwraps a layer of encryption, and then determines who is next to get the data packet. Eventually, the data request makes it to the correct computer, and a response is sent back in the same manner. </p>
<p>Any sort of internet connection can be made through a Tor network – HTML web browsing, piracy torrents, email, Internet Relay Chat, and so on and so forth. To an external observer, the network looks like a game of Chinese whispers. For someone observing a computer acting as a relay for these messages, it isn’t possible to determine which messages going in correspond to which messages going out. </p>
<p>At an exit node, however, all connections are “in the clear”. This is the point where surveillance operations have managed to intervene so far. Now there is concern that government surveillance may be able to expand beyond this, and crack the whole Tor network wide open.</p>
<h2>Completely cracked, or just a scare campaign?</h2>
<p>The most <a href="http://www.theguardian.com/world/2013/oct/04/nsa-gchq-attack-tor-network-encryption">recent news pieces</a> detail how Tor is “close” to being compromised, or that it can be hacked or cracked. </p>
<p>The disclosures include PowerPoint slides from the NSA in 2007 referring to the Tor problem (or, according to the slides, “Tor Stinks”), and then again in 2012 noting the continuing difficulty that Tor poses for surveillance. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/32549/original/f9xytjfm-1381115977.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/32549/original/f9xytjfm-1381115977.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/32549/original/f9xytjfm-1381115977.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/32549/original/f9xytjfm-1381115977.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/32549/original/f9xytjfm-1381115977.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/32549/original/f9xytjfm-1381115977.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/32549/original/f9xytjfm-1381115977.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Michael Kappel</span></span>
</figcaption>
</figure>
<p>The messages around these stories are largely the same as stories of security breaches from <a href="http://archives.seul.org/or/talk/Jan-2010/msg00161.html">2010</a>, but with some indication that there has been a small degree of success. </p>
<p>The NSA admits in their slides that it will be impossible to do anything other than track a very very small number of users.</p>
<p>Metrics on the Tor network have absolutely skyrocketed in the <a href="https://metrics.torproject.org/users.html">past two months</a>, more than quadrupling since mid-August. This coincides with the release of the custom-made <a href="http://piratebrowser.com">Pirate Browser</a> – a free and easy way to connect to the Tor network.</p>
<p>This is possibly the reason for the recent press releases about the cracking of the network – it may be easier to scare people away from Tor, rather than cracking the network itself. </p>
<p>As the takedown of a Tor hidden service operator company <a href="http://arstechnica.com/tech-policy/2013/09/fbi-admits-what-we-all-suspected-it-compromised-freedom-hostings-tor-servers/">Freedom Hosting shows</a>, Tor is most vulnerable to external attacks, such as physically removing servers.</p>
<p>It’s worth keeping in mind that the NSA is simply one of many organisations attempting to subvert the Tor network. </p>
<p>As much as the US government has become the nemesis of many privacy advocates, it is worth remembering that governments in Russia and China are well-known for their surveillance operations, and their frankly <a href="https://theconversation.com/greenpeace-piracy-charges-mock-international-law-18867">brutish response</a> to dissident activity.</p>
<p>So while it isn’t 100% secure, Tor seems to be a pretty secure way to keep your online movements private.</p><img src="https://counter.theconversation.com/content/18945/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robbie Fordyce does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>You may have seen reports over the weekend about yet another instalment of the US National Security Agency’s (NSA) surveillance system - this time a set of slides focused on cracking the Tor network, a…Robbie Fordyce, PhD candidate, School of Culture and Communication and Institute for a Broadband-Enabled Society, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.