I recently attended a very engaging lecture at the London School of Economics (LSE) by Prof David Lyon – who spoke about “Identity as Surveillance – Security, Surveillance and Citizenship”.

I do hope he subsequently saw this article from the BBC, on the opening day of the Labour Party Conference: “Lord Mandelson denied entry to conference“, because I’m sure it would give him a good laugh.

Apparently, the Noble Lord, First Secretary of State, Secretary of State for Business, Innovation and Skills, President of the Board of Trade and Lord President of the Council could not, initially, get into the conference because there was a problem with his pass. Maybe they couldn’t fit his title onto it. The press were naturally quick to savour the irony that Peter Mandelson, the man perhaps most identified with New Labour, should be unable to identify himself to the satisfaction of the party’s gatekeepers.

What this has to do with Prof Lyon’s talk is this: one of his themes was the way in which identity systems (particularly national ones) permit, enable and encourage judgements to be made about individuals on the basis of “actuarial criteria”, even if other methods would be more reliable (and more respectful of personal privacy).

An example Prof Lyon gave was this: research work by John Taylor and Miriam Lips (full text of paper available online here) investigated the use of online identity data by the DVLA ([UK] Driver and Vehicle Licensing Agency) when someone applies online for a driving licence. The researchers noted that the DVLA submits the applicant’s details to the credit reference company Experian, which attempts to corroborate the applicant’s identity assertions by matching them against databases of Credit Applications and Addresses. Experian then applies a weighting which assigns a ‘trust score’ to the applicant’s assertions, based on the apparent quality of the applicant’s digital footprint (as revealed by the database enquiries). These actuarial measurements are then used by the DVLA to govern the subsequent processing of the application transaction.

Prof Lyon’s point was that this ‘trust score’ mechanism goes beyond a simple assessment of whether or not the applicant’s address can be corroborated. The score is enhanced more, for instance, if the applicant’s records indicate that they have had a lot of interactions with clearing banks, than if the indication is that the applicant has had a lot of interactions with mail-order companies.

The implication of this is that subsequent processing of the DVLA application is determined not just by past records, but by inferences based on supposed future behaviours of the applicant – whether or not those inferences are in fact accurate.

Basically, this is what starts to happen, the more you architect systems on the basis of actuarial criteria in support of the categorisation of individuals, and the more you remove notions of human judgement and discretion from the process. Admittedly, that’s not always a bad thing – after all, humans are fallible too. But if you design humans into the process rather than out of it, you get fewer embarassing incidents such as the sight of Labour’s “eminence grise” being locked out of his own conference…

Those of you with any interest in cricket will know that today is the first day of the 4th Test Match between Australia and England for the Ashes. With the series standing at 1-0 to England (2 matches having ended in a draw), the 4th Test (out of 5) could be the clincher. Not that I’m a cricket buff in any way – but it’s a good excuse to get a couple of those bewildering sports analogies into the blog post. (See bottom of post for approximate baseball translations…)

The Home Office appeared to have been bowled a bit of a googly [1] yesterday, when it was reported that Adam Laurie had not only hacked the access controls on an ID Card chip, but had successfully copied the data onto another chip, modified an existing field and added new data in another. However, this piece on the Kable site reports that the Home Office played a straight bat [2], denying outright that there was any evidence of a successful or viable attack.

According to the spokesperson:

“This story is rubbish. We are satisfied the personal data on the chip cannot be changed or modified and there is no evidence this has happened,” said a spokesperson.”The identity card includes a number of design and security features that are extremely difficult to replicate. Furthermore, the card readers we will deploy will undertake chip authentication checks that the card produced will not pass. We remain confident that the identity card is one of the most secure of its kind, fully meeting rigorous international standards.”

What’s not quite clear is whether the phrase “personal data on the chip” has again been carefully chosen to allow for the possibility that personal data, once off the chip, could be modified successfully.

As for the comments about authentication checks between the card, the chip and the reader: I remember studying a similar design exercise when I was working with the IBM 4753 device family in the early ’90s. The 4753 was a smart card reader with an encrypting PIN pad; it included the option to connect to a 4755 cryptographic adapter (PC card), and also to have a biometric pen attached to it to produce a ‘digitised signature’. The pen incorporated three sensors (one for pressure, and one each for the two dimensions of movement across the page), which it used to generate a digital ‘map’ of your signature and thence a cryptographic hash of the resulting data. The ratio of false accepts/rejects to correct accepts/rejects was pretty impressive, and seemed consistent whether you ‘enrolled’ with your signature or with some other pass-phrase. Unfortunately it was all a bit pricey.

The other feature of the system was that each of the devices in a setup (the card reader, the crypto adapter and the smart card) was able to establish a pairwise, DES-encrypted session with each of the others.

This meant that the session keys had to form part of a standard DES key hierarchy (session/data keys, key-exchange keys, and master keys). The role of the master key in this hierarchy is to encrypt/decrypt the key-exchange keys. Good practice says that your master key should be unique to each hardware device, and should never leave a protective hardware key-storage module, or KSM. (Bear with me… this is going somewhere relevant…)

In the PC adapter and the card reader, that KSM was about the size of a pack of cards, had a long-life battery back-up and several hardware protective mechanisms to prevent physical attempts to extract the keys. My favourite was the low-temperature sensor; it had been observed that, if you cool a memory chip sufficiently and then slice away at it with a microtome (thing used for preparing stuff you want to put under an electron microscope… makes very thin slices…), you could reveal the physical record of ones and zeroes and, in principle, recover the keys (a bit like reading the pattern of pits on the surface of a CD through a microscope). The low temperature sensor was there so that, if the KSM thought someone might be trying this, it would wipe the keys from memory.

The point is that in the corresponding smart card format, the size constraints meant that it was impractical to apply several of these physical security measures – such as the temperature sensors or the battery backup. Lack of the latter meant that instead of being stored in volatile RAM, the smart card keys were written to EEPROM so that they could persist in the card.

The adapter/reader KSMs also had a Faraday shield to prevent attempts to ‘eavesdrop’ on the module while it was at work. Obviously, that’s not very practical in the smart card implementation, though, if you want to use contactless communication between the card and a reader.

The bottom line is that, at least back then, the security of the key-store smart card depended to a great extent on the fact that it was very small, and was physically sandwiched between other parts of the chip. It was still more vulnerable to physical attack than its larger siblings, and such attacks were demonstrated by Ross Anderson and his students at the Cambridge University Computer Laboratory. (Incidentally, these physical attacks – and much more – are described in Prof Anderson’s 600-page book on Security Engineering, freely available online here, which is a belter of a read if you’re at all interested in this sort of thing).

The point is that whatever authentication protocols the smart card and reader undertake, the security of that communication is very likely to depend, ultimately, on the physical security of the smart card – and that imposes design constraints which can be extremely hard to overcome, especially if you want a card which is affordable at population scales of deployment.

Adam Laurie’s current attack may or may not be fatal in principle, and may or may not be viable in practice. It’s impossible to tell, from the level of information in the public domain – but by the same token, it is also impossible to conclude, from that information, whether or not these ID card chips genuinely increase the security and integrity of the bearer’s data.

All in all, a very sticky wicket [3].

[1] googly : a ball which appears to be heading in one direction, but instead breaks the other way. Rough translation – a pitch which starts out looking like a Sinker, but turns into a Cutter (remember that in cricket the ball can hit the ground before reaching the batsman… which gives an opportunity for an abrupt change of direction).

[2] play a straight bat : to maintain a resolute defence, often by playing a ‘blocking shot’ – though offensive strokes can also be played with a straight bat. ‘Keeping a straight bat’ is a general principle which relates to the wisdom of keeping your bat well aligned with the (vertical) stumps it is used to defend. No direct equivalent in baseball, because in cricket the batsman has the option of hitting the ball and not running… but technically, the closest equivalent might be a bunt.

[3] sticky wicket : an unpredictable or difficult playing surface – hence, unpredictable or difficult circumstances. Again, no direct equivalent, because it refers to the area the ball bounces off before reaching the batsman.

PS – at the time of writing, England are all out for a paltry 102 runs, while Australia have scored 79 for the loss of just one wicket. Not looking good for England.

• March 2006 – UK introduces RFID-enabled, ICAO-compliant ‘e-passports’;
• March 2007 – Adam Laurie demonstrates ability to unlock e-passport chip data for ‘read’ access;
• August 2008 – Jeroen van Beek demonstrates ability to clone e-passport chip and implant bogus images;
• August 2009 – Same techniques applied to clone UK ID card and modify its data.

Technological progress being what it is, we can already see – over the 3 years since their introduction – the erosion of some of the security features of the RFID implementation: for instance, in response to the August 2008 attack, the Home Office responded that

“it had yet to see evidence of someone being able to manipulate data in an e-passport. A spokesman said: “No one has yet been able to demonstrate that they are able to modify, change or alter data within the chip. If any data were to be changed, modified or altered it would be immediately obvious to the electronic reader.”

Note the careful phrasing there: “data in an e-passport”. What the attacks have demonstrated is that you can read the information off a chip, write it to another chip, and modify that version in such a way that it fools the standard UN/ICAO “Golden Reader” software. These two pages give more details and are a useful counter-balance to the “e-passports cracked, nation doomed” headlines:

• Q&A about Jeroen van Beek’s hack, from 2008;
• Register article on “how to clone an e-passport”, from Aug 4th 2006 (yes, 3 years ago last Tuesday!)

So, should we be surprised at this sequence of hacks? In one sense, no: essentially, all it illustrates is one of a set of basic principles about credentials. The diagram below shows how these attacks fit into that set of principles: in this instance, the ‘weak link’ comes when an authenticating party relies exclusively on the RFID chip to establish the connection between the credential and the person presenting it.

This diagram is just the latest embodiment of something I’ve been using since about 2005 to illustrate what I call the “chain of trust”. That is: the purpose of a credential is to provide some level of proof that the person presenting it now ‘is identical with’ the person to whom it was issued. This is a narrow but very useful definition of the term ‘identity’. What level of proof the credential can provide depends on the strength of several factors over the lifetime of the credential (and, indeed, its bearer).

In the current sequence of hacks, what is being tested is the integrity of the credential as a whole (can bogus data be successfully encapsulated in a credential which appears genuine?), and the robustness of the authentication step (does it rely solely on the credential, or does it also involve comparison with an ‘authoritative’ repository?).

The Home Office, IPS and ICAO have all pointed out that the attacks fail to overcome some of the safeguards built into the system as a whole. For instance, ICAO note that the passport hack would be revealed by a check against their PKD database; the UK authorities point out that a cloned ID card with the user’s details modified will fail a check against the National Identity Register (assuming that that repository still contains the details of the user to whom the card was originally issued). Those defences are all true – but they do not prove that the implementation of these RFID chips is secure as a whole. They show that it is secure in certain use cases – for instance, when the card is not used as a stand-alone authentication mechanism, but is used in conjunction with online access to other components of the system (such as the PKD or the National Identity Register) – and that checks against those components are, in turn, secure. The also show that in some entirely realistic use-cases – for instance, where an online check against the NIR or deployment of full-function card readers would be prohibitively expensive – the level of proof the credentials can deliver is substantially reduced.

Again, the answer to the question ‘should this surprise us?’ is probably ‘no’. On the other hand, let’s not forget that successive proponents of the ID card scheme have given a hostage to fortune in the form of the phrase “the gold standard of identity”. Some of them have even referred to commercial organisations “queueing up to rely on it as proof of identity”. It is one thing to proclaim this as a political aspiration; it is, as the hacks have demonstrated since the chips’ introduction, quite another to translate that into a comprehensive implementation which delivers the same ‘gold standard’ to all relying parties.

Several people I’ve spoken to recently have remarked that real-time social media like Twitter seem to reduce the frequency with which they blog… and I suspect it’s the same for me. It’s partly because Twitter soaks up time, and partly because it also soaks up some of those spur-of-the-moment ideas and comments which otherwise might have developed into fully-fledged postings. However, looked at the right way, I guess that might also signal a flight to quality rather than quantity of blog posts. Here’s hoping…

But I digress – or whatever a digression is called when it comes at the beginning, rather than part way through.

I’ve just got back from last week’s Burton Catalyst conference in San Diego – an excellent event, by the way, and congratulations to the Burton Group analysts who did such a good job of adding value, both through their own subject-matter expertise and by making introductions and connections so constructively between attendees. Over lunch, I got into a discussion with one of the analysts about the UK National Identity Scheme (NIS), whether or not it was a good idea, and whether or not there are reliable grounds for opposing it. As ever, discussing UK policy while abroad gave a great opportunity to look at it from a different perspective.

The view he expressed was, essentially, that there isn’t a good reason to oppose ID Cards on the basis of their use for e-government service delivery – the benefit of reliable authentication for joined-up government is worth having; however, there’s a risk involved if you suspect that the government lacks the competence to run such a scheme securely, and that risk might outweigh the potential benefit.

There were two other points which we noted and then moved on:

• first, that there are those who feel the National Identity Scheme is currently unaffordable;
• second, that cancelling the ‘small, visible, individual plastic card’ component of the system does nothing to mitigate the risk of operating the large, invisible, mass-scale repositories’ component of the system.

So, what of the question of competence? Well, the picture revealed by ComputerWeekly‘s FoI requests is not entirely reassuring. They list a number of breaches involving inappropriate insider access to records in the CIS (Customer Information System) database, one of the three major repositories in the Scheme. On the one hand, some breaches are indeed being discovered and those responsible are being disciplined (including dismissal). A DWP spokesman is quoted as saying that “the small number of incidents shows that the CIS security system is working”.

On the other hand, the article questions whether all breaches are actually being noticed (and/or reported), and suggests that many were only discovered after sample checks, rather than through alerts being triggered.

There’s also the issue of how many people have, or will have, access to the data held in the NIS. Currently it stands at about 200,000 civil servants, across 480 local government bodies and a number of central government departments. That figure will increase as data-sharing between the CIS and other departments such as the DVLA (Driver and Vehicle Licensing Agency) is put in place. Interestingly, a case study on the DWP’s own website gives this description of the DVLA’s ‘purpose of use’ for access to the CIS:

“to confirm receipt of higher rate mobility component of Disability Living Allowance for entitlement to exemption of vehicle licensing duty”

That’s really quite specific. Indeed, it might lead one to wonder whether that purpose makes it proportionate to expose the CIS’ 92,000,000 records to the DVLA user population. It’s not easy to find out the size of that population, but according to the DVLA’s annual report for 2007-2008 there were about 6,500 people on their payroll (this does not necessarily include those employed as part of ‘contracted-out services’, a separate item in the accounts).

The stated purpose also makes it legitimate to wonder what safeguards are in place to ensure that the data are not accessed for other purposes. The DVLA itself does not have an especially happy history where data sharing is concerned. After it reported £6.3m of income from selling motorists’ information to third parties, the government drafted new rules on acceptable use and sharing.

Returning, then, to the question of competence to run the National Identity Scheme securely: the DWP says it’s doing a good job of keeping the CIS secure, despite a small number of identified insider breaches; but the CIS is only one of three major repositories in the Scheme, each owned by a different department. All three of them need protecting if the whole is to be meaningfully secure. Then there’s the issue of securing access by ‘user’ departments such as the DVLA: the difficulty of doing that grows with each department added, and the growth is almost certainly exponential rather than linear.

Posted June 18, 2009

There’s a nice, succinct article in the FT today (also available online here) reading the runes on the Home Office’s contractual arrangements for parts of the ID Cards scheme. At the heart of the story is the issue that contractual timescales and the policy-making calendar don’t always align very tidily, particularly when a general election has to be factored in within the next 350 days.

As the FT article notes:

“The Home Office has already signed four contracts in the ID programme: a pilot scheme run by Thales; a passport and ID card application system being developed by US-based CSC; an IBM contract to build a database to store fingerprint and facial biometrics; and a De La Rue contract to produce biometric passports.

These, however, could be left largely untouched by the Tories, because much of the technology would be needed to introduce biometric passports, which the party supports.”

So the current ID Card implementation policy may indeed have been ‘kicked into the long grass’ for the time being… but when the next election rolls around, I suspect the public will be looking much more closely than they did last time at any manifesto commitments relating to national-scale databases of identity data, facial/fingerprint/iris biometrics, DNA and the like.

PS – I should also include a link to this article in today’s Guardian, partly because it raises very lucid points about the future of a database state, and partly to note that any similarity between their opening paragraphs and my blog post of Monday 15th are doubtless entirely co-incidental :^)

–posted by Robin Wilton, Director of Privacy and Public Policy, Liberty Alliance

Posted June 16, 2009

Dear Home Secretary,

Welcome to your new post. I hope your advisers have put in your in-tray a copy of the very lucid analysis of the UK’s National Identity Scheme which Toby Stevens has written here on his ComputerWeekly blog. His starting point is to wonder whether your appointment as Home Secretary signals the opportunity to abandon the government’s ID Card policy, and he then draws out some of the many reasons why that policy has degenerated into a probably irredeemable mess.

As to the first question – I agree with Toby’s assessment. It would be a brave Home Secretary, in the current government, who repealed a piece of primary legislation which, in your own words, embodies a manifesto commitment. On the face of it, there seems little sense in handing the opposition, within bow-shot of the next general election, the PR victory of being able to claim that Labour has finally accepted what the Conservatives and Lib Dems have been saying all along… that the Identity Cards Act 2006 has got to go.

However, as the rest of Toby’s post goes on to illustrate, this is by no means just about the Act. The Act itself is a product of the government’s policy objectives, and has to be reflected in policies and implementation if it is to have any practical effect. That relatively flexible relationship between the primary legislation and the practicalities of ID Cards is at once your opportunity and your burden.

It’s an opportunity in the sense that it leaves the way open (as this Guardian article suggests) for you to pay lip service to the Act – implementing it in a couple of well-circumscribed instances – while investing no effort in rolling out a comprehensive national ID Cards scheme.

But it’s a burden in many senses. First, as I say, the Act is a product of the government’s policy objectives… but so many years and Home Secretaries have passed since those policy objectives were first conceived, and political necessities have forced so many twists, tweaks and back-trackings on them that it is, fundamentally, no longer clear why the government wants a National Identity Card, what benefits it expects from one, and what it would do with it if it had one.

Second, your choices are constrained by the flaw which is built into the Act’s very title: it is, unusually, a piece of primary legislation explicitly framed in terms of a specific technology – an identity card. And yet, when push comes to shove, you would doubtless ditch the card itself, if that gave you the leeway to, as Toby puts it, carry on with “biometric passports and the centralisation of biometric and biographical information into the National Identity Register. In other words, all that will change is that we won’t receive the bit of plastic – everything else will continue regardless”.

How can it have come to this – a national identity infrastructure which omits the very thing named in its own primary legislation? On one level, the answer to that question is simple: we’ve arrived at this state of affairs because successive justifications of the National Identity Scheme have sought to portray it as different things. It’s a counter-terrorism measure; it’s to prevent benefit fraud; it’s to cut health-care costs; it’s to secure the UK’s borders; it’s an entitlement card (remember that one?); it’s “the gold standard of identity”, which businesses will queue up to trust… and my favourite: it’s a conveniently portable alternative to a paper passport, for young ladies who want to carry proof of age when they go clubbing.

Unfortunately, these justifications are all ad hoc, and range from the politically expedient to the absurd. They have never been underpinned by a clear, robust and explicit statement of principles to which all the legitimate stakeholders have signed up. And there are multiple legitimate stakeholders here: public admininstration, law enforcement, commerce… oh, and the citizen/cardholder.

My plea is this: be explicit about who the stakeholders are, and acknowledge their legitimate interests, even if those are many, varied and sometimes conflicting. Have the courage to call out the fact that the Act, as drafted, is fundamentally flawed. Explain to the citizen that the small piece of plastic is actually entirely irrelevant, and the important, useful and dangerous part is the National Identity Register.

Be open and honest about the policy purpose of the National Identity Scheme, and what the National Identity Card and the National Identity Register have to do with it. Set out a clear statement of principles which reflects the aims of the government and the interests of the stakeholders – and be prepared to ditch anything which does not put those principles into practice, whether that’s the Act, the Card, the Register or the policy.

Yours sincerely,

Robin Wilton

–posted by Robin Wilton, Director of Privacy and Public Policy, Liberty Alliance