Category Archives: Internet censorship

Online traceability: Who did that?

Consumer Focus have recently published my expert report on the issues that arise when attempting to track down people who are using peer to peer (P2P) systems to share copyright material without appropriate permissions. They have submitted this report to Ofcom who have been consulting on how they should regulate this sort of tracking down when the Digital Economy Act 2010 (DEA) mechanisms that are intended to prevent unlawful file sharing finally start to be implemented, probably sometime in 2014.

The basic idea behind the DEA provisions is that the rights holders (or more usually specialist companies) will join the P2P systems and download files that are being shared unlawfully. Because the current generation of P2P systems fails to provide any real anonymity, the rights holders will learn the IP addresses of the wrongdoers. They will then consult public records at RIPE (and the other Regional Internet Registries) to learn which ISPs were allocated the IP addresses. Those ISPs will then be approached and will be obliged, by the DEA, to consult their records and tell the appropriate account holder that someone using their Internet connection has been misbehaving. There are further provisions for telling the rights holders about repeat offenders, and perhaps even for “technical measures” to disrupt file sharing traffic.

From a technical point of view, the traceability part of the DEA process can (in principle) be made to work in a robust manner. However, there’s a lot of detail to get right in practice, both in recording the data generated by the P2P activity and within the ISPs systems — and history shows that mistakes are often made. I have some first hand experience of this, my report refers to how I helped the police track down a series of traceability mistakes that were made in a 2006 murder case! Hence I spend many pages in my report explaining what can go wrong and I set out in considerable detail the sort of procedures that I believe that Ofcom should insist upon to ensure that mistakes are rare and are rapidly detected.

My report also explains the difficulties (in many cases the insuperable difficulties) that the account holder will have in determining the individual who was responsible to the P2P activity. Consumer Focus takes the view that “this makes the proposed appeals process flawed and potentially unfair and we ask Government to rethink this process”. Sadly, there’s been no sign so far that this sort of criticism will derail the DEA juggernaut, although some commentators are starting to wonder if the rights holders will see the process as passing a cost/benefit test.

Call for Papers: Internet Censorship and Control

I am co-editing a special edition of IEEE Internet Computing on Internet Censorship and Control. We are looking for short (up to 5,000 words) articles on the technical, social, and political mechanisms and impacts of Internet censorship and control. We’re soliciting both technical and social science articles, and especially encourage those that combine the two. Appropriate topics include

  • explorations of how the Internet’s technical, social, and political structures impact its censorship and control;
  • evaluations of how existing technologies and policies affect Internet censorship and control;
  • proposals for new technologies and policies;
  • discussions on how proposed technical, legal, or governance changes to the Internet will impact censorship and control;
  • analysis of techniques, methodologies, and results of monitoring Internet censorship and control; and
  • examinations of trade-offs between control and freedom, and how these sides can be balanced.

Please email the guest editors a brief description of the article you plan to submit by 15 August 2012. For further details, see the full CFP. Please distribute this CFP, and use this printable flyer if you wish.

Call for nominations for PET Award 2012

Nominations are invited for the 2012 PET Award by 31 March 2012.

The PET Award is presented annually to researchers who have made an outstanding contribution to the theory, design, implementation, or deployment of privacy enhancing technology. It is awarded at the annual Privacy Enhancing Technologies Symposium (PETS).

The PET Award carries a prize of 3000 USD thanks to the generous support of Microsoft. The crystal prize itself is offered by the Office of the Information and Privacy Commissioner of Ontario, Canada.

Any paper by any author written in the area of privacy enhancing technologies is eligible for nomination. However, the paper must have appeared in a refereed journal, conference, or workshop with proceedings published in the period from 1 June 2010 until 31 March 2012.

For eligibility requirements, refer to the award rules.

Anyone can nominate a paper by sending an email message containing the following to award-chairs12@petsymposium.org:

  • Paper title
  • Author(s)
  • Author(s) contact information
  • Publication venue and full reference
  • Link to an available online version of the paper
  • A nomination statement of no more than 500 words.

All nominations must be submitted by 31 March 2012. The Award Committee will select one or two winners among the nominations received. Winners must be present at the 2012 PET Symposium in order to receive the Award. This requirement can be waived only at the discretion of the PET Advisory board.

More information about the PET award (including past winners) is see the award website.

Bankers' Christmas present

Every Christmas we give our friends in the banking industry a wee present. Sometimes it’s the responsible disclosure of a vulnerability, which we publish the following February: 2007’s was PED certification, 2008’s was CAP while in 2009 we told the banking industry of the No-PIN attack. This year too we have some goodies in the hamper: watch our papers at Financial Crypto 2012.

In other years, we’ve had arguments with the bankers’ PR wallahs. In 2010, for example, their trade association tried to censor one of our students’ thesis. That saga also continues; Britain’s bankers tried once more to threaten us so we told them once more to go away. We have other conversations in progress with bankers, most of them thankfully a bit more constructive.

This year’s Christmas present is different: it’s a tale with a happy ending. Eve Russell was a fraud victim whom Barclays initially blamed for her misfortune, as so often happens, and the Financial Ombudsman Service initially found for the bank as it routinely does. Yet this was clearly not right; after many lawyers’ letters, two hearings at the ombudsman, two articles in The Times and a TV appearance on Rip-off Britain, Eve won. This is the first complete case file since the ombudsman came under the Freedom of Information Act; by showing how the system works, it may be useful to fraud victims in the future.

For your Christmas entertainment, we offer the bank statement which told Eve of the fraud; the initial exchange of letters between Eve’s lawyers and the bank; the ombudsman’s routine initial ruling against Eve, and her protest; the correspondence between the ombudsman and Barclays; Eve’s appeal and expert opinion; the verdict; and the offer of settlement. And let’s not forget the Thunder. A Merry Christmas to all!

DNSChanger might change the BGPSEC landscape

In early November, a sophisticated fraud was shut down and a number of people arrested. Malware from a family called “DNSChanger” had been placed on around four million machines (Macs as well as Windows machines) over several years.

The compromised users had their DNS traffic redirected to criminally operated servers. The main aim of the criminals seems to have been to redirect search queries and thereby to make money from displaying adverts.

Part of the mitigation of DNSChanger involves ISC running DNS servers for a while (so that 4 million people whose DNS servers suddenly disappear don’t simultaneously ring their ISP helpdesks complaining that the Internet is broken).

To prevent bad people running the DNS servers instead, the address blocks containing the IPs of the rogue DNS servers which used to belong to the criminals (but are now pointed at ISC) have been “locked”.

This is easy for ARIN (the organisation who looks after North American address space) to acquiesce to, because they have US legal paperwork compelling their assistance. However, the Dutch police have generated some rather less compelling paperwork and served that on RIPE; so RIPE is now asking the Dutch court to clarify the position.

Further details of the issues with the legal paperwork can be found on (or linked from) the Internet Governance Project blog. The IGP is a group of mainly but not entirely US academics working on global Internet policy issues.

As the IGP rightly point out, this is going to be an important case because it is going to draw attention to the role of the RIRs — just at the time when that role is set to become even more important.

As we move to crypto-secured BGP routing, the RIRs (ARIN, RIPE etc) will be providing cryptographic assurance of the validity of address block ownership. Which means, in effect, that we are building a system where the courts in one country (five countries in all, for five RIRs) could remove ISPs and hosting providers from the Internet… and some ISPs [and their governments] (who are beginning to think ahead) are not entirely keen on this prospect.

If, as one might expect, the Dutch courts eventually uphold the DNSChanger compulsion on RIPE (even if the Dutch police have to have a second go at making the paperwork valid) then maybe this will prove the impetus to abandon a pyramid structure for BGP security and move to a “sea of certificates” model (where one independently chooses from several overlapping roots of authority) — which more closely approximates the reality of a global system which touches a myriad set of local jurisdictions.

Will LBT be blocked?

Back in July I wrote a blog article “Will Newzbin be blocked?” which discussed the granting of an injunction to a group of movie companies to force BT to block access to “Newzbin2“.

The parties were back in court this last week to hammer out the exact details of the injunction.

The final wording of the injunction requires BT to block customer access to Newzbin2 by #1(1) rerouting traffic to relevant IPs and #1(2) applying “DPI based” URL blocking. The movie companies have to tell BT which IPs and which URLs are relevant.

#2 of the injunction says that BT can use its existing “Cleanfeed” system (which I wrote about here and at greater length in my PhD thesis here) to meet the requirements of #1, even though Cleanfeed isn’t believed to use DPI at all !

#3 and #4 of the injunction allows the parties to agree to suspend blocking and to come back to court in the future, and #5 relates to the costs of the court action.

One of the (few) upsides of this injunction will be to permit lawful experimentation as to the effectiveness of the Cleanfeed system, assuming that it is used — if the studios ask for all URLs on a website to be blocked, I expect that null routing the website entirely will be simpler for BT than redirecting traffic to the Cleanfeed proxy.

Up until now, discovering a flaw in the technical implementation of Cleanfeed would result in successful access to a child sexual abuse image website. Anyone monitoring the remote end of the connection might then draw the conclusion that images had been viewed and a criminal offence committed. Although careful experimental design could avoid law-breaking, it might be some time into the investigation process before this was properly understood by the criminal justice system, and the intervening period would be somewhat stressful for the investigator.

There is no law that prevents viewing of the contents of Newsbin2, and so the block circumvention techniques proposed over the past few years (starting of course with just using “https”) can now start to be evaluated as to their actual effectiveness.

However, there is more to #1 of the injunction, in that it applies to:

[…] www.newzbin.com, its domains and sub-domains and including payments.newzbin.com and any other IP address or URL whose sole or predominant purpose is to enable or facilitate access to the Newzbin2 website.

I don’t expect that publishing circumvention experience here on LBT could be seen as the predominant purpose of this blog… so I don’t really expect these pages to suddenly become invisible to BT customers. But, since the whole process has an Alice in Wonderland feel to it (someone who believes that blocking websites is possible clearly had little else to do before breakfast), it cannot be entirely ruled out.

Trusted Computing 2.1

We’re steadily learning more about the latest Trusted Computing proposals. People have started to grok that building signed boot into UEFI will extend Microsoft’s power over the markets for AV software and other security tools that install around boot time; while ‘Metro’ style apps (i.e. web/tablet/html5 style stuff) could be limited to distribution via the MS app store. Even if users can opt out, most of them won’t. That’s a lot of firms suddenly finding Steve Ballmer’s boot on their jugular.

We’ve also been starting to think about the issues of law enforcement access that arose during the crypto wars and that came to light again with CAs. These issues are even more wicked with trusted boot. If the Turkish government compelled Microsoft to include the Tubitak key in Windows so their intelligence services could do man-in-the-middle attacks on Kurdish MPs’ gmail, then I expect they’ll also tell Microsoft to issue them a UEFI key to authenticate their keylogger malware. Hey, I removed the Tubitak key from my browser, but how do I identify and block all foreign governments’ UEFI keys?

Our Greek colleagues are already a bit cheesed off with Wall Street. How happy will they be if in future they won’t be able to install the security software of their choice on their PCs, but the Turkish secret police will?

Debate at Cambridge Festival of Ideas: Internet Freedom

In the evening of Thursday 27 October, I will be participating in a debate at the Cambridge Festival of Ideas, on Internet Freedom. Other speakers include Jim Killock, executive director of the Open Rights Group, Herbert Snorsson, founder of Openleaks.org and David Clemente, Chatham House. Further details can be found on the festival website.

Attendance is free, but booking is required.

DCMS illustrates the key issue about blocking

This morning the Department for Culture Media and Sport (DCMS) have published a series of documents relating to the implementation of the Digital Economy Act 2010.

One of those documents, from OFCOM, describes how “Site Blocking” might be used to prevent access to websites that are involved in copyright infringement (ie: torrent sites, Newzbin, “cyberlockers” etc.).

The report appears, at a quick glance, to cover the ground pretty well, describing the various options available to ISPs to block access to websites (and sometimes to block access altogether — since much infringement is not “web” based).

The site also explains how each of the systems can be circumvented (and how easily) and makes it clear (in big bold type) “All techniques can be circumvented to some degree by users and site owners who are willing to make the additional effort.

I entirely agree — and seem to recall a story from my childhood about the Emperor’s New Blocking System — and note that continuing to pursue this chimera will just mean that time and money will be pointlessly wasted.

However OFCOM duly trot out the standard line one hears so often from the rights holders: “Site blocking is likely to deter casual and unintentional infringers and by requiring some degree of active circumvention raise the threshold even for determined infringers.

The problem for the believers in blocking is that this just isn’t true — pretty much all access to copyright infringing material involves the use of tools (to access the torrents, to process NZB files, or just to browse [one tends not to look at web pages in Notepad any more]). Although these tools need to be created by competent people, they are intended for mass use (point and click) and so copyright infringement by the masses will always be easy. They will not even know that the hurdles were there, because the tools will jump over them.

Fortuitously, the DCMS have provided an illustration of this in their publishing of the OFCOM report…

The start of the report says “The Department for Culture, Media and Sport has redacted some parts of this document where it refers to techniques that could be used to circumvent website blocks. There is a low risk of this information being useful to people wanting to bypass or undermine the Internet Watch Foundation‟s blocks on child sexual abuse images. The text in these sections has been blocked out.

What the DCMS have done (following in the footsteps of many other incompetents) is to black out the text they consider to be sensitive. Removing this blacking out is simple but tedious … you can get out a copy of Acrobat and change the text colour to white — or you can just cut and paste the black bits into Notepad and see the text.

So I confidently expect that within a few hours, non-redacted (non-blocked!) versions of the PDF will be circulating (they may even become more popular than the original — everyone loves to see things that someone thought they should not). The people who look at these non-blocked versions will not be technically competent, they won’t know how to use Acrobat, but they will see the material.

So the DCMS have kindly made the point in the simplest of ways… the argument that small hurdles make any difference is just wishful thinking; sadly for Internet consumers in many countries (who will end up paying for complex blocking systems that make no practical difference) these wishes will cost them money.

PS: the DCMS do actually understand that blocking doesn’t work, or at least not at the moment. Their main document says “Following advice from Ofcom – which we are publishing today – we will not bring forward site blocking regulations under the DEA at this time.” Sadly however, this recognition of reality is too late for the High Court.

Will Newzbin be blocked?

This morning the UK High Court granted an injunction to a group of movie companies which is intended to force BT to block access to “newzbin 2” by their Internet customers. The “newzbin 2″ site provides an easy way to search for and download metadata files that can be used to automate the downloading of feature films (TV shows, albums etc) from Usenet servers. ie it’s all about trying to prevent people from obtaining content without paying for a legitimate copy (so called “piracy“).

The judgment is long and spends a lot of time (naturally) on legal matters, but there is some technical discussion — which is correct so far as it goes (though describing redirection of traffic based on port number inspection as “DPI” seems to me to stretch the jargon).

But what does the injunction require of BT? According to the judgment BT must apply “IP address blocking in respect of each and every IP address [of newzbin.com]” and “DPI based blocking utilising at least summary analysis in respect of each and every URL available at the said website and its domains and sub domains“. BT is then told that the injunction is “complied with if the Respondent uses the system known as Cleanfeed“.

There is almost nothing about the design of Cleanfeed in the judgment, but I wrote a detailed account of how it works in a 2005 paper (a slightly extended version of which appears as Chapter 7 of my 2005 PhD thesis). Essentially it is a 2-stage system, the routing system redirects port 80 (HTTP) traffic for relevant IP addresses to a proxy machine — and that proxy prevents access to particular URLs.

So if BT just use Cleanfeed (as the injunction indicates) they will resolve newzbin.com (and www.newzbin.com) which are currently both on 85.112.165.75, and they will then filter access to http://www.newzbin.com/, http://newzbin.com and http://85.112.165.75. It will be interesting to experiment to determine how good their pattern matching is on the proxy (currently Cleanfeed is only used for child sexual abuse image websites, so experiments currently pose a significant risk of lawbreaking).

It will also be interesting to see whether BT actually use Cleanfeed or if they just ‘blackhole’ all access to 85.112.165.75. The quickest way to determine this (once the block is rolled out) will be to see whether or not https://newzbin.com works or not. If it does work then BT will have obeyed the injunction but the block will be trivial to evade (add a “s” to the URL). If it does not work then BT will not be using Cleanfeed to do the blocking!

BT users will still of course be able to access Newzbin (though perhaps not by using https), but depending on the exact mechanisms which BT roll out it may be a little less convenient. The simplest method (but not the cheapest) will be to purchase a VPN service — which will tunnel traffic via a remote site (and access from there won’t be blocked). Doubtless some enterprising vendors will be looking to bundle a VPN with a Newzbin subscription and an account on a Usenet server.

The use of VPNs seems to have been discussed in court, along with other evasion techniques (such as using web and SOCKS proxies), but the judgment says “It is common ground that, if the order were to be implemented by BT, it would be possible for BT subscribers to circumvent the blocking required by the order. Indeed, the evidence shows the operators of Newzbin2 have already made plans to assist users to circumvent such blocking. There are at least two, and possibly more, technical measures which users could adopt to achieve this. It is common ground that it is neither necessary nor appropriate for me to describe those measures in this judgment, and accordingly I shall not do so.

There’s also a whole heap of things that Newzbin could do to disrupt the filtering or just to make their site too mobile to be effectively blocked. I describe some of the possibilities in my 2005 academic work, and there are doubtless many more. Too many people consider the Internet to be a static system which looks the same from everywhere to everyone — that’s just not the case, so blocking systems that take this as a given (“web sites have a single IP address that everyone uses”) will be ineffective.

But this is all moot so far as the High Court is concerned. The bottom line within the judgment is that they don’t actually care if the blocking works or not! At paragraph #198 the judge writes “I agree with counsel for the Studios that the order would be justified even if it only prevented access to Newzbin2 by a minority of users“. Since this case was about preventing economic damage to the movie studios, I doubt that they will be so sanguine if it is widely understood how to evade the block — but the exact details of that will have to wait until BT have complied with their new obligations.