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05 October 2017
Mike Rosulek
In this paper we consider optimizing garbled circuits for the gate-hiding case. We observe that the best state-of-the-art constructions support only a limited class of gate functions, which turns out to undermine their improvements in several settings. These state-of-the-art constructions also require a non-minimal hardness assumption.
We introduce two new gate-hiding constructions of garbled circuits. Both constructions achieve the same communication complexity as the best state-of-the-art schemes, but support a more useful class of boolean gates and use only the minimal assumption of a secure PRF.
Christopher Ambrose, Joppe W. Bos, Björn Fay, Marc Joye, Manfred Lochter, Bruce Murray
Muoi Tran, Loi Luu, Min Suk Kang, Iddo Bentov, Prateek Saxena
Sarvar Patel, Giuseppe Persiano, Kevin Yeo
As in SSE, every construction of a SSEwSU will be a trade-off between efficiency and security, as measured by the amount of leakage. In multi-user settings, we must also consider cross-user leakage (x-user leakage) where a query performed by one user would leak information about the content of documents shared with a different user.
We start by presenting two strawman solutions that are at the opposite side of the efficiency-leakage bidimensional space: x-uz, that has zero x-user leakage but is very inefficient, and x-uL, that is very efficient but highly insecure with very large x-user leakage. We give a third construction, x-um, that is as efficient as x-uL and more efficient than x-uz. At the same time, x-um is considerably more secure than x-uL. Construction x-um is based on the concept of a Re-writable Deterministic Hashing (RDH), which can be thought of as a two-argument hash function with tokens that add re-writing capabilities. Sharing and unsharing in x-um is supported in constant (in the number of users, documents, and keywords) time. We give a concrete instantiation whose security is based on the Decisional Diffie-Hellman assumption. We provide a rigorous analysis of x-um and show a tight bound on the leakage in the presence of an active adversary that corrupts a subset of the users. We report on experimental work that show that x-um is very efficient and x-user leakage grows very slowly as queries are performed by the users.
Additionally, we present extensions of x-um. We modify x-um to support a finer grained access granularity, so a document can be shared to a user either only for reading (i.e., searching) or for writing (i.e., editing). We also extend x-um to the bilinear setting to further reduce leakage.
Michel Abdalla, Dario Catalano, Dario Fiore, Romain Gay, Bogdan Ursu
Abdelrahaman Aly, Sara Cleemput
Jia Xu, Ee-Chien Chang, Jianying Zhou
Bei Liang, Aikaterini Mitrokotsa
03 October 2017
Sarani Bhattacharya, Clementine Maurice, Shivam Bhasin, Debdeep Mukhopadhyay
Zvika Brakerski, Alex Lombardi, Gil Segev, Vinod Vaikuntanathan
Our approach extends and refines the recent tree-based approach of Cho et al. (CRYPTO '17) and Döttling and Garg (CRYPTO '17). Whereas the tools underlying their approach do not seem to provide any form of anonymity, we introduce two new building blocks which we utilize for achieving anonymity: blind garbled circuits (which we construct based on any one-way function), and blind batch encryption (which we construct based on CDH).
We then further demonstrate the applicability of our newly-developed tools by showing that batch encryption implies a public-key encryption scheme that is both resilient to leakage of a $(1-o(1))$-fraction of its secret key, and KDM secure (or circular secure) with respect to all linear functions of its secret key (which, in turn, is known to imply KDM security for bounded-size circuits). These yield the first high-rate leakage-resilient encryption scheme and the first KDM-secure encryption scheme based on the CDH or Factoring assumptions.
Finally, relying on our techniques we also construct a batch encryption scheme based on the hardness of the Learning Parity with Noise (LPN) problem, albeit with very small noise rate $\Omega(\log^2(n)/n)$. Although this batch encryption scheme is not blind, we show that it still implies standard (i.e., non-anonymous) IBE, leakage resilience and KDM security. IBE and high-rate leakage resilience were not previously known from LPN, even with extremely low noise.
Andreas H\"{u}lsing, Lea Rausch, Johannes Buchmann
Andreas H{\"u}lsing
Vienna, Austria, 16 October 2017
Singapore University of Technology and Design (SUTD)
I am looking for postdocs / research fellows with expertise on cyber-physical system security, especially on the legacy CPS protection. The candidates should have track record of strong R&D capability, be able to perform deep system-level investigations of security mechanisms, be a good team player, and also have good written/oral communication skills. The position will provide an excellent opportunity to perform both basic and translational research in close collaboration with industry. Successful candidates will be offered internationally competitive remuneration, and enjoy high-quality living and low tax rates in Singapore.
Interested candidates please send your CV with a research statement to Prof. Jianying Zhou.
Contact: Prof. Jianying Zhou
Email: jianying_zhou (at) sutd.edu.sg
Home: http://jianying.space/
Closing date for applications: 31 October 2017
Contact: Prof. Jianying Zhou
More information: http://jianying.space/
McMaster University
DIGITAL MANUFACTURING, IOT AND/OR CYBER-PHYSICAL SYSTEMS
Candidates must have a Doctorate in Engineering and must possess excellent communication skills and demonstrated ability in classroom and lab instruction at the university level. Experience in developing state-of-the-art experimental set-ups, supervision of open-ended design projects and demonstrated interest in pedagogy are essential. Familiarity with electronic learning platforms and experiential learning methodologies is required. Experience with C++ and VB.Net programming, MATLAB, LabVIEW, and web technologies/programming are definite assets. Postdoctoral or industrial experience will be considered favorably. Professional engineering license, or eligibility for registration, is crucial. Demonstrated ability to work effectively with individuals from diverse communities and cultures is valued.
While the primary role for this position is teaching (24 credit hours per year), the School expects faculty to engage in committee assignments and to participate in student and school events, as well as other service tasks, as assigned.
The appointment will be contractually limited for a period of up to 3 years in length commencing July 1, 2017 with the possibility of extension. Salary is competitive and commensurate with experience and qualifications. Review of applications will begin immediately and continue until the position is filled.
Closing date for applications: 29 October 2017
More information: http://www.eng.mcmaster.ca/wbooth/index.html
01 October 2017
Sarvar Patel, Giuseppe Persiano, Kevin Yeo
Additionally, we present Twice-Recursive Square Root ORAM (TR-SQRT) with smaller client stor- age requirements. Due to its flexibility, we construct several instantiations under different memory requirements. TR-SQRT is asymptotically competitive with previous results, yet remarkably simple.
30 September 2017
Ruhr-Universität Bochum, Germany
We are looking for a junior scientist with a visible research profile in Cryptography, in particular in theoretical cryptography, provable security, protocols, or secure multiparty computation. The successful applicant is expected to get actively involved in the Horst Görtz Institute for IT-Security. Teaching responsibilities will include service teaching duties of the Department of Mathematics.
The initial appointment will be for three years; upon successful evaluation, the position will be extended for further three years.
We expect:
• strong commitment to academic teaching;
• readiness to participate in interdisciplinary research;
• willingness and ability to attract external funding;
• readiness to contribute to joint research projects of the department.
Application deadline: November 12th 2017
Closing date for applications: 12 November 2017
Contact: Eike Kiltz
More information: http://www.ruhr-uni-bochum.de/ffm/pdf/W1_Kryptographie_en.pdf
Aggelos Kiayias, Andrew Miller, Dionysis Zindros
Christophe Petit, Kristin Lauter
Jos\'{e} Becerra, Petra Sala, Marjan \v{S}krobot
In this paper, we revisit zkPAKE, an augmented PAKE that has been recently proposed by Mochetti, Resende, and Aranha (SBSeg 2015). Our work shows that the zkPAKE protocol is prone to offline password guessing attack, even in the presence of an adversary that has only eavesdropping capabilities. Therefore, zkPAKE is insecure and should not be used as a key exchange mechanism.