|
Jefferson's WheelSecurity Research at the University of Virginia |
Yuchen Zhou won the Rader Graduate Research Award for Computer Engineering! This award from the Department of Electrical and Computer Engineering recognizes outstanding research by a Computer Engineering PhD student.
I gave a keynote talk at the Applied Multi-Party Computation workshop at Microsoft Research Redmond on Multi-Party Computation in 2029: Boom, Bust, or Bonanza?. Despite the risk of being proved horribly wrong in 15 years, my slides are here (also available as [PPTX] and as a video):
There are well-written summaries of the talk by Mahnush Movahedi and Mahdi Zamani and the Aarhus Crypto Group.
Karsten Nohl, who complete a PhD in our group in 2009, is visiting UVa this week. UVa Today has an article: Renowned ‘White Hat Hacker’ to Speak on Real-World Security Holes:
University of Virginia graduate Karsten Nohl, one of the world’s most famous “white hat computer hackers,” will speak Friday at 3:30 p.m. in Rice Hall, room 130, about lessons learned from the security holes that he and fellow researchers have uncovered in mobile phones, wireless car keys and other technology used by billions of people everyday.
Nohl first made international headlines in 2008, while still a computer engineering doctoral student at U.Va., for research that exposed vulnerabilities in the world’s most popular smartcard, used by millions of people to pay fares on several major mass-transit systems around the world, including the London Underground and the Boston subway.
Such cards utilize miniscule wireless computer chips, about the size of a grain of rice, called RFIDs, short for “radio-frequency identification.” They send and receive information over short distances (generally 10 feet or less) via very low-power radio waves.As an ethical security researcher, often called a “white hat hacker,” Nohl exposes vulnerabilities to spur improvements in the systems that he researches. He now does such work around the world as the founder and director of research at Security Research Labs in Berlin.
To prevent those with nefarious purposes from exploiting security holes he uncovers, Nohl typically withholds key details of the exploit and discloses his findings only months after sharing his research with the relevant manufacturers or trade organizations to allow them to roll out upgrades or countermeasures to mitigate the security risk.
Since graduating from U.Va. in August 2008, Nohl has gone on to discover and demonstrate two key security vulnerabilities in mobile phones – encryption flaws in both the GSM protocol that most cell phones use to communicate with cell towers, and in SIM cards, the tiny “subscriber identity module” chip in every phone that identifies and authenticates the phone.
Both discoveries generated worldwide media coverage.
As just one example of possible ramifications, the latter security hole could allow a malicious hacker to send a virus through a text message, which could then allow the hacker to eavesdrop on calls or make purchases through mobile payment systems.
“Karsten has had an outstanding impact in analyzing how cryptography gets used in the real world and demonstrating what goes wrong when important engineering principles are not followed carefully,” said computer science professor David Evans, Nohl’s former doctoral adviser and a co-organizer of Friday’s talk. “The vulnerabilities he has identified in RFID algorithms, GSM encryption and SIM cards impact billions of devices most of us use every day, and it’s really important that people understand the security weaknesses in these systems and that vendors work to improve them. Karsten’s work is a fundamental step toward those goals.”
Nohl’s talk will discuss how security exploits with real-world implications are usually enabled by not just one design flaw, but by deviations from best practices on multiple design layers. Protection designs that focus on a single security function and neglect complementary layers are more prone to compromise, Nohl will argue, with examples from his own research on three widely deployed technologies – cell phones, car keys and smartcards.
“Real-world cryptographic systems rarely meet academic expectations, with most systems being shown ‘insecure’ at some point,” Nohl said in an email description of his talk. “At the same time, our IT-driven world has not yet fallen apart, suggesting that many protection mechanisms are ‘secure enough’ for how they are employed.”
The talk will be followed by a reception in the fourth-floor atrium of Rice Hall.
The event is co-sponsored by the departments of Computer Science and Electrical and Computer Engineering, which jointly administer U.Va.’s computer engineering Program in the School of Engineering and Applied Science.
Security exploits nearly always stem from attackers finding ways to violate assumptions system implementers relied upon. As a simple example, consider a classic buffer overflow attack which is possible because the implementers assumed (perhaps implicitly) that the size of some data could not exceed the buffer size, but an attacker found a way to create an input that violates that assumption.
In this work, joint with colleagues at Microsoft Research, we consider the implicit assumptions upon which secure use of single sign-on SDKs depends. Our study of three important authentication and authorization SDKs (including Facebook’s) supports the need for systematically explicating SDKs to uncover these assumptions. We found assumptions that were critical to secure use of the SDKs, but that were not clearly documented and were subtle enough to be missed by the majority of tested apps.
We advocate that a systematic explication process for uncovering these assumptions should be part of the engineering process for developing security-critical SDKs.
For details, see our paper:
Our paper on symmetric cut-and-choose is now available. The paper will be presented at CRYPTO 2013 in August.
Abstract. Beginning with the work of Lindell and Pinkas, researchers have proposed several protocols for secure two-party computation based on the cut-and-choose paradigm. In existing instantiations of this paradigm, one party generates k garbled circuits; some fraction of those are “checked” by the other party, and the remaining fraction are evaluated. We introduce here the idea of symmetric cut-and-choose protocols, in which both parties generate k circuits to be checked by the other party. The main advantage of our technique is that k can be reduced by a factor of 3 while attaining the same statistical security level as in prior work. Since the number of garbled circuits dominates the costs of the protocol, especially as larger circuits are evaluated, our protocol is expected to run up to 3 times faster than existing schemes. Preliminary experiments validate this claim.
Full paper (16 pages): [PDF]
Jonathan Burket has been recognized with a CRA Outstanding Undergraduate Researcher Honorable Mention. This award recognizes outstanding research by undergraduate students in North America.
Jonathan joined our research group as a first year student (recruited from cs1120) and has done several research projects focused on web security including working on GuardRails and leading a new research project on correlating web application state and requests with behavior such as database requests.
Congratulations to Jonathan!
Fraudulent mobile applications could trick users into entering sensitive passwords, and then send those passwords to rogue site operators. With current technologies, users have no way of knowing that when they enter a password it is going to the intended application. What is needed is a trusted path for password entry, so when users enter a password they can trust that it will only be visible to the trusted provider.
This paper presents a solution that does not require any modifications to existing apps or application servers, but modifies the Android kernel to establish a shared secret between the user and kernel as part of the boot process, and then uses that shared secret to provide a trusted path for password entry.
Tianhao Tong will present the paper at Moble Security Technologies (MoST) in San Francisco, CA, 23 May 2013.
Paper: Tianhao Tong and David Evans. GuarDroid: A Trusted Path for Password Entry. In Moble Security Technologies (MoST), San Francisco, CA, 23 May 2013. [PDF, 10 pages]
Code: GuarDroid.net
Samee Zahur and I have written a paper on Circuit Structures for Improving Efficiency of Security and Privacy Tools. The paper explores ways to design static circuits (as used in garbled circuit protocols and symbolic execution, among other things) to provide reasonable efficiency for algorithms that use common data structures like arrays. By taking advantage of somewhat predictable access patterns, as well as batching, our circuit structures are able to provide operations with amortized cost that is polylogarithmic in the size of the data structure (in contrast to naive approaches that would require effectively copying the entire data structure for each operation). Samee will present the paper at the IEEE Symposium on Security and Privacy (“Oakland”) in San Francisco in May.
Full paper (15 pages): [PDF]
Project: MightBeEvil.com/netlist
Code: http://github.com/samee/netlist
Our paper on strengthening secure computation protocols to resist stronger adversaries is now available:
Yan Huang, Jonathan Katz, and David Evans. Quid Pro Quo-tocols: Strengthening Semi-Honest Protocols with Dual Execution. In 33rd IEEE Symposium on Security and Privacy (“Oakland” 2012), San Francisco, CA. 20-23 May 2012. [PDF, 13 pages]
Yan Huang will present the paper at the Oakland conference (which will be held in San Francisco for the first time, after being in Berkeley/Oakland for the first 32 years!) in May.
Abstract: Known protocols for secure two-party computation that are designed to provide full security against malicious behavior are significantly less efficient than protocols intended only to thwart semi-honest adversaries. We present a concrete design and implementation of protocols achieving security guarantees that are much stronger than are possible with semi-honest protocols, at minimal extra cost. Specifically, we consider protocols in which a malicious adversary may learn a single (arbitrary) bit of additional information about the honest party’s input. Correctness of the honest party’s output is still guaranteed. Adapting prior work of Mohassel and Franklin, the basic idea in our protocols is to conduct two separate runs of a (specific) semi-honest, garbled-circuit protocol, with the parties swapping roles, followed by an inexpensive secure equality test. We provide a rigorous definition and prove that this protocol leaks no more than one additional bit against a malicious adversary. In addition, we propose some enhancements to reduce the overall information a cheating adversary learns. Our experiments show that protocols meeting this security level can be implemented at cost very close to that of protocols that only achieve semi-honest security. Our results indicate that this model enables the large-scale, practical applications possible within the semi-honest security model, while providing dramatically stronger security guarantees.
Full paper (13 pages): [PDF]
Project site: MightBeEvil.com
I gave a talk today at the University of Richmond on secure computation, targeted to a general audience. [Richmond Abstract Page]
Two-party secure computation allows two parties to compute a function that depends on inputs from both parties, but reveals nothing except the output of the function. A general solution to this problem have been known since Andrew Yao’s pioneering work on garbled circuits in the 1980s, but only recently has it become conceivable to use this approach in real systems. This talk will provide an introduction to secure computation, and describe the work we are doing at UVa to make secure computation efficient and scalable enough to build real applications. The talk assumes no prior background in cryptography, and should be understandable all computing students.
For more, see: MightBeEvil.com
