Computer Laboratory

Security Group

2014 seminars

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18 March 15:00Bitcoin: A Full Employment Act for security engineers? / Joseph Bonneau, Center For Information Technology Policy, Princeton

Lecture Theatre 2, Computer Laboratory, William Gates Building

This talk will provide a brief overview of Bitcoin and discuss why it has been a fascinating new area of security research spanning crypto, security economics, game theory, and anonymity. A few case studies will highlight some of the surprising new applications and research findings, as well as discussing why Bitcoin is far more limited in its current version that is commonly assumed.

Joseph Bonneau is a fellow at the Center For Information Technology Policy, Princeton. He is focused on web security, authentication, and TLS, though his past research has spanned side-channel cryptanalysis, protocol verification, software obfuscation, and privacy in social networks.

He completed his PhD in 2012 with the Security Group of the University of Cambridge Computer Laboratory, supervised by Professor Ross Anderson and funded as a Gates Cambridge Scholar. His PhD thesis formalises the analysis of human-chosen distributions of secrets, specifically passwords and PINs.

His background is in computer science, math, and cryptography, in which he earned his BS and MS from Stanford. He's worked on cryptography and security at Google, Cryptography Research, Inc and as a private consultant.

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25 February 15:00Introduction to DNSSEC / Tony Finch, University of Cambridge Computing Service

Lecture Theatre 2, Computer Laboratory, William Gates Building

This talk is a quick introduction to DNSSEC, the Domain Name System Security extensions. DNSSEC is interesting because it does more than just add tamper-proofing to the DNS: it is also a new public-key infrastructure.

The talk will describe the security features that DNSSEC adds (and does not add) to the DNS, and how the DNSSEC PKI can support other protocols such as SSL/TLS and SSH.

To be useful, DNSSEC needs to be widely deployed. The talks will demonstrate that switching on DNSSEC can be straight-forward, and will mention some of the traps and pitfalls that can catch the unwary.

Talk slides and materials are at

Tony Finch is a system administrator and developer in the University of Cambridge Information Services (until recently known as the Computing Service) where he helps to run the mail and DNS systems. He has contributed to a number of open source projects including Exim, BIND, SpamAssassin, FreeBSD, Apache httpd, and git. He participates in a number of IETF working groups related to mail and DNS, and has contributed draft documents to the DANE working group.

He is mildly notorious for his email address, and can be found online at

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11 February 15:00On the (in)security of widely-used RFID access control systems / Dr. Flavio D. Garcia, University of Birmingham

Lecture Theatre 2, Computer Laboratory, William Gates Building

Over the last few years much attention has been paid to the (in)security
of the cryptographic mechanisms used in RFID and contactless smart
cards. Experience has shown that the secrecy of proprietary ciphers does
not contribute to their cryptographic strength. Most notably the Mifare
Classic, which has widespread application in public transport ticketing
(e.g. Oyster) and access control systems, has been thoroughly broken in
the last few years. Other prominent examples include KeeLoq and Hitag2
used in car keys and CryptoRF used in access control and payment systems.

This talk summarizes our own contribution to this field. We will
briefly show some of the weaknesses we found in the Mifare classic. Then
we will show that the security of its higher-end competitors like
Atmel's CryptoRF and HID's iClass – which were proposed as secure
successors of the Mifare Classic – is not (significantly) higher. We will
also cover security issues of the Hitag2 key fob to conclude with a
discussion on responsible disclosure principles.

Garcia is a faculty member in the Birmingham's Security and Privacy
Group, and is currently employed as a “Birmingham Fellow”. His work
focuses on the design and evaluation of cryptographic primitives and
protocols for small embedded devices like RFID and smart cards. His
research achievements include breakthroughs such as the discovery of
vulnerabilities in Mifare Classic, iClass, CryptoMemory and HiTag2. The
first of these, Mifare Classic, was widely used for electronic payment
(e.g. London Underground) and access control (e.g. Amsterdam Airport).
Garcia showed that the cryptography in the card was fatally flawed.
HiTag2, the most widely used key fob used in car keys was also found to
be insecure.

Garcia’s work has been widely recognised as world leading including
“Best Paper” awards from the leading IEEE Security & Privacy and Usenix
Woot conferences and the 2008 I/O Award from the Dutch research council
for the best paper bringing computer science research to the attention
of the general public. Garcia joined the security group at the
University of Birmingham in February 2013.

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04 February 15:00The effect of decentralized behavioral decision making on system-level risk / Kim Kaivanto, Lancaster University

Lecture Theatre 2, Computer Laboratory, William Gates Building

Certain classes of system-level risk depend partly on decentralized lay decision making. For
instance, an organization’s network security risk depends partly on its employees’ responses
to phishing attacks. On a larger scale, the risk within a financial system depends partly on
households’ responses to mortgage sales pitches. Behavioral economics shows that lay decision
makers typically depart in systematic ways from the normative rationality of Expected Utility
(EU), and instead display heuristics and biases as captured in the more descriptively accurate
Cumulative Prospect Theory (CPT). In turn psychological studies show that successful decep-
tion ploys eschew direct logical argumentation and instead employ peripheral-route persuasion,
manipulation of visceral emotions, urgency, and familiar contextual cues. Signal Detection The-
ory (SDT) offers the standard normative solution, formulated as an optimal cutoff threshold,
for distinguishing between good/bad emails or mortgages. In this paper we extend SDT be-
haviorally by re-deriving the optimal cutoff threshold under CPT. Furthermore we incorporate
the psychology of deception into determination of SDT’s discriminability parameter. With the
neo-additive probability weighting function, the optimal cutoff threshold under CPT is rendered
unique under well-behaved sampling distributions, tractable in computation, and transparent
in interpretation. The CPT-based cutoff threshold is (i) independent of loss aversion and (ii)
more conservative than the classical SDT cutoff threshold. Independently of any possible mis-
alignment between individual-level and system-level misclassification costs, decentralized behav-
ioral decision makers are biased toward under-detection, and system-level risk is consequently
greater than in analyses assuming normative rationality.

Kim's research issues from a core interest in decision making under risk and uncertainty. He works with both normative and descriptive behavioural mathematical models as well as the associated empirical models, and he designs and implements laboratory experiments for testing normative and behavioural hypotheses. Kim's recent projects have addressed questions in the areas of cyber security and financial decision making. Kim is Director of the recently established Lancaster Experimental Economics Laboratory (LExEL) and a member of the LUMS Research Ethics Committee.

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21 January 15:00Eavesdropping near field contactless payments: A quantitative analysis / Thomas P. Diakos, University of Surrey

Lecture Theatre 2, Computer Laboratory, William Gates Building

We present a quantitative assessment in terms of frame error rates for the
success of an eavesdropping attack on a contactless transaction using easily
concealable antennas and low cost electronics. An inductive loop, similar
in size to those found in mobile devices equipped with NFC capabilities,
was used to emulate an ISO 14443 transmission. For eavesdropping we used an
identical loop antenna as well as a modified shopping trolley. Synchronisation
and frame recovery were implemented in software. As a principal result of
our experiments we present the FER achieved over a range of eavesdropping
distances, up to 1m, at different magnetic field strengths within the range
specified by the ISO 14443 standard.

Thomas is a PhD candidate at the University of Surrey, looking into the
security and privacy of near field contactless payments. He is currently
investigating how a combination of remote interrogation and eavesdropping
could be used to extract information from contactless devices that could
potentially cause financial or anonymity loss for the victim. Following his
military service, he studied for a BEng in electrical engineering from the
University of Sheffield and an MSc in communications and signal processing
from the University of Bristol.

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14 January 15:00Privacy/Proxy/Perfidy – what criminals (and others) put in domain whois / Dr Richard Clayton, University of Cambridge

Lecture Theatre 2, Computer Laboratory, William Gates Building

I've recently completed a major study of the 'whois' contact details for
domain names used in malicious or harmful Internet activities. ICANN
wanted to know if a significant percentage of these domain registrations
used a privacy or proxy services to obscure the perpetrator’s identity ?
No surprises in our results: Yes!

What was perhaps surprising was that quite a significant percentage of
domains used for lawful and harmless activities ALSO used privacy and
proxy services.

But the real distinction is that when domains are maliciously
registered, then contact details are hidden in a range of different ways
so that 9 out 10 of these registrants are a priori uncontactable –
whereas the uncontactable rate varies between a quarter and at most two-
thirds for the non-malicious registrations.

This talk discusses how these results were obtained and what their
implications are for the future of the whois system. It also gives some
technical insight into the innovative design of whois parsing tool that
has enabled some extremely variable reporting formats to be handled, at
substantial scale, in an automated manner.

Richard Clayton came back to Cambridge in 2000 to study for a PhD on
'Anonymity and Traceability in Cyberspace'. Since getting his degree he
has stayed on as an academic PostDoc "because it's more fun than
working". The main focus of his research is on cybercrime, and
particularly on 'phishing'. The ICANN project described in this talk was
done during his recently completed three year collaboration with the
National Physical Laboratory (NPL) on the EPSRC funded project "Internet