I’m at the 24th security protocols workshop in Brno (no, not Borneo, as a friend misheard it, but in the Czech republic; a two-hour flight rather than a twenty-hour one). We ended up being bumped to an old chapel in the Mendel museum, a former monastery where the monk Gregor Mendel figured out genetics from the study of peas, and for the prosaic reason that the Canadian ambassador pre-empted our meeting room. As a result we had no wifi and I have had to liveblog from the pub, where we are having lunch. The session liveblogs will be in followups to this post, in the usual style.
All posts by Ross Anderson
Met police chief blaming the victims
Commissioner Hogan-Howe of the Met said on Thursday that the banks should not refund fraud victims because it “rewards” them for being lax about internet security. This was too much to pass up, so I wrote a letter to the editor of the Times, which has just been published. As the Times is behind a paywall, here is the text.
Sir, Sir Bernard Hogan-Howe argues that banks should not refund online fraud victims as this would make people careless with their passwords and anti-virus software (p1, March 24, and letters Mar 25 & 26). This is called secondary victimisation. Thirty years ago, a chief constable might have said that rape victims had themselves to blame for wearing nice clothes; if he were to say that nowadays, he’d be sacked. Hogan-Howe’s view of bank fraud is just as uninformed, and just as offensive to victims.
About 5 percent of computers running Windows are infected with malware, and common bank fraud malware such as Zeus lets the fraudster redirect transactions. You think you’re paying £150 to your electricity bill, while the malware is actually sending £9000 to Russia. The average person is helpless against this; everything seems normal, and antivirus products usually only detect it afterwards.
Much of the blame lies with the banks, who let the users of potentially infected computers make large payments instantly, rather than after a day or two, as used to be the case. They take this risk because regulators let them dump much of the cost of the resulting fraud on customers.
The elephant in the room is that the Met has been claiming for years that property crime is falling, when in fact it’s just going online like everything else. We’re now starting to get better crime figures; it’s time we got better policing, and better bank regulation too.
Ross Anderson FRS FREng
Professor of Security Engineering
University of Cambridge
What do we mean by scale?
Online booking is now open for the annual Lovelace lecture, which I’m giving in London on March 15th. I’ll be using the event to try to develop a cross-cutting theme that arises from my research but is of wider interest. What do we mean by scale?
Back when computing was expensive, computer science started out worrying about how computations scaled – such as which sorting algorithms ran as n², n log n or even n. Once software development became the bottleneck, we started off by trying the same approach (measuring code entropy or control graph complexity), but moved on to distinguishing what types of complexity could be dealt with by suitable tools. Mass-market computing and communications brought network effects, and scalability started to depend on context (this is where security economics came in). Now we move to “Big Data” the dependency on people becomes more explicit. Few people have stopped to think of human factors in scaling terms. Do we make information about many people available to many, or to few? What about the complexity of the things that can be done with personal data? What about costs now versus in the future, and the elasticity of demand associated with such costs? Do you just count the data subjects, do you count the attackers too, or do you add the cops as well?
I’ve been quoted as saying “You can have security, functionality, scale – choose any two” or words to that effect. I’ll discuss this and try to sketch the likely boundaries, as well as future research directions. The discussion will cross over from science and engineering to economics and politics; recent proposed legislation in the UK, and court cases in the USA, would impose compliance burdens on people trying to scale systems up from one country to many.
The students we’re training to be the next generation of developers and entrepreneurs will need a broader understanding of what’s involved in scaling systems up, and in this talk I’ll try to explore what that means. Maybe I’m taking a risk with this talk, as I’m trying to assemble into a row a lot of facts that are usually found in different columns. But I do hope it will not be boring.
Financial Cryptography 2016
I will be trying to liveblog Financial Cryptography 2016, which is the twentieth anniversary of the conference. The opening keynote was by David Chaum, who invented digital cash over thirty years ago. From then until the first FC people believed that cryptography could enable commerce and also protect privacy; since then pessimism has slowly set in, and sometimes it seems that although we’re still fighting tactical battles, we’ve lost the war. Since Snowden people have little faith in online privacy, and now we see Tim Cook in a position to decide which seventy phones to open. Is there a way to fight back against a global adversary whose policy is “full take”, and where traffic data can be taken with no legal restraint whatsoever? That is now the threat model for designers of anonymity systems. He argues that in addition to a large anonymity set, a future social media system will need a fixed set of servers in order to keep end-to-end latency within what chat users expect. As with DNS we should have servers operated by (say ten) different principals; unlike in that case we don’t want to have most of the independent parties financed by the US government. The root servers could be implemented as unattended seismic observatories, as reported by Simmons in the arms control context; such devices are fairly easy to tamper-proof.
The crypto problem is how to do multi-jurisdiction message processing that protects not just content but also metadata. Systems like Tor cost latency, while multi-party computation costs a lot of cycles. His new design, PrivaTegrity, takes low-latency crypto building blocks then layers on top of them transaction protocols with large anonymity sets. The key component is c-Mix, whose spec up as an eprint here. There’s a precomputation using homomorphic encryption to set up paths and keys; in real-time operations each participating phone has a shared secret with each mix server so things can run at chat speed. A PrivaTegrity message is four c-Mix batches that use the same permutation. Message models supported include not just chat but publishing short anonymous messages, providing an untraceable return address so people can contact you anonymously, group chat, and limiting sybils by preventing more than one pseudonym being used. (There are enduring pseudonyms with valuable credentials.) It can handle large payloads using private information retrieval, and also do pseudonymous digital transactions with a latency of two seconds rather than the hour or so that bitcoin takes. The anonymous payment system has the property that the payer has proof of what he paid to whom, while the recipient has no proof of who paid him; that’s exactly what corrupt officials, money launderers and the like don’t want, but exactly what we do want from the viewpoint of consumer protection. He sees PrivaTegrity as the foundation of a “polyculture” of secure computing from multiple vendors that could be outside the control of governments once more. In questions, Adi Shamir questioned whether such an ecosystem was consistent with the reality of pervasive software vulnerabilities, regardless of the strength of the cryptography.
I will try to liveblog later sessions as followups to this post.
Report on the IP Bill
This morning at 0930 the Joint Committee on the IP Bill is launching its report. As one of the witnesses who appeared before it, I got an embargoed copy yesterday.
The report s deeply disappointing; even that of the Intelligence and Security Committee (whom we tended to dismiss as government catspaws) is more vigorous. The MPs and peers on the Joint Committee have given the spooks all they wanted, while recommending tweaks and polishes here and there to some of the more obvious hooks and sharp edges.
The committee supports comms data retention, despite acknowledging that multiple courts have found this contrary to EU and human-rights law, and the fact that there are cases in the pipeline. It supports extending retention from big telcos offering a public service to private operators and even coffee shops. It support greatly extending comms data to ICRs; although it does call for more clarity on the definition, it give the Home Office lots of wriggle room by saying that a clear definition is hard if you want to catch all the things that bad people might do in the future. (Presumably a coffee shop served with an ICR order will have no choice but to install a government-approved black box. or just pipe everything to Cheltenham.) It welcomes the government decision to build and operate a request filter – essentially the comms database for which the Home Office has been trying to get parliamentary approval since the days of Jacqui Smith (and which Snowden told us they just built anyway). It comes up with the rather startling justification that this will help privacy as the police may have access to less stuff (though of course the spooks, including our 5eyes partners and others, will have more). It wants end-to-end encrypted stuff to be made available unless it’s “not practicable to do so”, which presumably means that the Home Secretary can order Apple to add her public key quietly to your keyring to get at your Facetime video chats. That has been a key goal of the FBI in Crypto War 2; a Home Office witness openly acknowledged it.
The comparison with the USA is stark. There, all three branches of government realised they’d gone too far after Snowden. President Obama set up the NSA review group, and implemented most of its recommendations by executive order; the judiciary made changes to the procedures of the FISA Court; and Congress failed to renew the data retention provisions in the Patriot Act (aided by the judiciary). Yet here in Britain the response is just to take Henry VIII powers to legalise all the illegal things that GCHQ had been up to, and hope that the European courts won’t strike the law down yet again.
People concerned for freedom and privacy will just have to hope the contrary. The net effect of the minor amendments proposed by the joint committee will be to make it even harder to get any meaningful amendments as the Bill makes its way through Parliament, and we’ll end up having to rely on the European courts to trim it back.
For more, see Scrambling for Safety, a conference we held last month in London on the bill and whose video is now online, and last week’s Cambridge symposium for a more detailed analysis.
More on the IP bill
I’m in a symposium at Churchill College on the Investigatory Powers Bill. It’s organised by John Naughton and I’ll be speaking later on equipment interference, a topic on which I wrote an expert report for the recent IP Tribunal case brought by Privacy International. Meanwhile I’ll try to liveblog the event in followups to this post.
Can we crowdsource trust?
Your browser contains a few hundred root certificates. Many of them were put there by governments; two (Verisign and Comodo) are there because so many merchants trust them that they’ve become ‘too big to fail’. This is a bit like where people buy the platform with the most software – a pattern of behaviour that let IBM and then Microsoft dominate our industry in turn. But this is not how trust should work; it leads to many failures, some of them invisible.
What’s missing is a mechanism where trust derives from users, rather than from vendors, merchants or states. After all, the power of a religion stems from the people who believe in it, not from the government. Entities with godlike powers that are foisted on us by others and can work silently against us are not gods, but demons. What can we do to exorcise them?
Do You Believe in Tinker Bell? The Social Externalities of Trust explores how we can crowdsource trust. Tor bridges help censorship victims access the Internet freely, and there are not enough of them. We want to motivate lots of people to provide them, and the best providers are simply those who help the most victims. So trust should flow from the support of the users, and it should be hard for powerful third parties to pervert. Perhaps a useful mascot is Tinker Bell, the fairy in Peter Pan, whose power waxes and wanes with the number of children who believe in her.
Scrambling for Safety X
Today I’m at the tenth Scrambling for Safety which is being held at Kings College London. Sorry, all the tickets are sold out, but there is a video feed available from the Open Rights Group website.
Snoopers’ Charter 2.0
This afternoon at 4.30 I have been invited to give evidence in Parliament to the Joint Select Committee on the Investigatory Powers Bill.
This follows evidence I gave on the technical aspects of the bill to the Science and Technology Committee on November 10th; see video and documents. Of particular interest may be comments by my Cambridge colleague Richard Clayton; an analysis by my UCL colleague George Danezis; the ORG wiki; and finally the text of the bill itself.
While the USA has reacted to the Snowden revelations by restraining the NSA in various ways, the UK reaction appears to be the opposite. Do we really want to follow countries like China, Russia and Kazakhstan, and take the risk that we’ll tip countries like Brazil and India into following our lead? If the Internet fragments into national islands, that will not only do grave harm to the world economy, but make life a lot harder for GCHQ too.
The emotional cost of cybercrime
We know more and more about the financial cost of cybercrime, but there has been very little work on its emotional cost. David Modic and I decided to investigate. We wanted to empirically test whether there are emotional repercussions to becoming a victim of fraud (Yes, there are). We wanted to compare emotional and financial impact across different categories of fraud and establish a ranking list (And we did). An interesting, although not surprising, finding was that in every tested category the victim’s perception of emotional impact outweighed the reported financial loss.
A victim may think that they will still be able to recover their money, if not their pride. That really depends on what type of fraud they facilitated. If it is auction fraud, then their chances of recovery are comparatively higher than in bank fraud – we found that 26% of our sample would attempt to recover funds lost in a fraudulent auction and approximately half of them were reimbursed (look at this presentation). There is considerable evidence that banks are not very likely to believe someone claiming to be a victim of, say, identity theft and by extension bank fraud. Thus, when someone ends up out of pocket, they will likely also go through a process of secondary victimisation where they will be told they broke some small-print rule like having the same pin for two of their bank cards or not using the bank’s approved anti-virus software, and are thus not eligible for any refund and it is all their own fault, really.
You can find the article here or here. (It was published in IEEE Security & Privacy.)
This paper complements and extends our earlier work on the costs of cybercrime, where we show that the broader economic costs to society of cybercrime – such as loss of confidence in online shopping and banking – also greatly exceed the amounts that cybercriminals actually manage to steal.