IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
01 October 2016
Jun Furukawa, Yehuda Lindell, Ariel Nof, Or Weinstein
ePrint ReportNirvan Tyagi, Yossi Gilad, Matei Zaharia, Nickolai Zeldovich
ePrint ReportThis paper presents Stadium, the first system to provide metadata and data privacy while being able to scale its work efficiently across many servers. Much like Vuvuzela, the current largest-scale system, Stadium is based on differential privacy. However, providing privacy in Stadium is more challenging because distributing users' traffic across servers creates opportunities for adversaries to observe it in fine granularity. To solve this challenge, Stadium uses a collaborative noise generation approach combined with a novel verifiable parallel mixnet design where servers collaboratively check that others follow the protocol. We show that Stadium can scale to use hundreds of servers, support over an order of magnitude more users than Vuvuzela, and cut the costs of operating each server.
Peeter Laud, Alisa Pankova
ePrint ReportThe execution of all branches introduces significant computational overhead. If the branches perform similar private operations, then it may make sense to compute repeating patterns only once, even though the necessary bookkeeping also has overheads. In this paper, we propose a program optimization doing exactly that, allowing the overhead of private conditionals to be reduced. The optimization is quite general, and can be applied to various privacy-preserving platforms.
Jian Bai, Dingkang Wang
ePrint Report29 September 2016
University of Helsinki, Finland
Job PostingCandidates for the doctoral student position should have completed a Master (or equivalent) degree in computer science, electrical engineering, mathematics, or other related field. We expect at least some experience and prior knowledge on cryptography, cryptographic protocols, or systems security. Candidates for the postdoctoral position should have completed their doctoral degree from a topic related to cryptography or information security and they are expected to have a good publication record. A candidate must be motivated, capable to take initiative, work independently, and be fluent in both written and spoken English.
Applications should be sent via email and should include a motivation letter, a full CV, a copy of the diploma with the grade transcript, a list of publications (for the postdoctoral position), and contact information for one or two persons who are willing to give references.
The applications will be reviewed immediately and the position will be filled when a suitable candidate is found.
Closing date for applications: 31 October 2016
Contact: Kimmo Järvinen, kimmo.jarvinen.crypto (at) gmail.com
Arpita Patra, Pratik Sarkar, Ajith Suresh
ePrint ReportWe present a fast OT extension protocol for small secrets in active setting. Our protocol when used to produce $1$-out-of-$n$ OTs outperforms all the known actively secure OT extensions. Our protocol is built on the semi-honest secure extension protocol of Kolesnikov and Kumaresan of CRYPTO'13 (referred as KK13 protocol henceforth) which is the best known OT extension for short secrets. At the heart of our protocol lies an efficient consistency checking mechanism that relies on the linearity of Walsh-Hadamard (WH) codes. Asymptotically, our protocol adds a communication overhead of $O(\mu \log{\kappa})$ bits over KK13 protocol irrespective of the number of extended OTs, where $\kappa$ and $\mu$ refer to computational and statistical security parameter respectively. Concretely, our protocol when used to generate a large enough number of OTs adds only $0.011-0.028\%$ communication overhead and $4-6\%$ runtime overhead both in LAN and WAN over KK13 extension. The runtime overheads drop below $2\%$ when in addition the number of inputs of the sender in the extended OTs is large enough.
As an application of our proposed extension protocol, we show that it can be used to obtain the most efficient PSI protocol secure against a malicious receiver and a semi-honest sender.
Brice Colombier, Lilian Bossuet, David Hély, Viktor Fischer
ePrint ReportSabyasachi Karati, Palash Sarkar
ePrint ReportNur Azman Abu, Shekh Faisal Abdul-Latip, Muhammad Rezal Kamel Ariffin
ePrint ReportVadim N. Tsypyschev
ePrint ReportPrevious work is available at http://eprint.iacr.org/2016/212
In this work we provide low rank estimations for sequences generated by two different designs based on coordinate sequences of linear recurrent sequences (LRS) of maximal period (MP) over Galois ring $R=GR(p^n,r)$, $p\ge 5$, $r\ge2$, with numbers $s$ such that $s=kr+2$, $k\in \mathbb{N}_0$, and based on digital sequences of coordinate sequences of matrix/skew MP LRS over such Galois rings.
Hannes Gross, Manuel Jelinek, Stefan Mangard, Thomas Unterluggauer, Mario Werner
ePrint ReportPrabhanjan Ananth, Aloni Cohen, Abhishek Jain
ePrint ReportIn this work, we continue this line of research, and perform a systematic study of updatable cryptography. We take a unified approach towards adding updatability features to recently studied cryptographic objects such as attribute-based encryption, functional encryption, witness encryption, indistinguishability obfuscation, and many others that support non-interactive computation over inputs. We, in fact, go further and extend our approach to classical protocols such as zero-knowledge proofs and secure multiparty computation.
To accomplish this goal, we introduce a new notion of updatable randomized encodings that extends the standard notion of randomized encodings to incorporate updatability features. We show that updatable randomized encodings can be used to generically transform cryptographic primitives to their updatable counterparts.
We provide various definitions and constructions of updatable randomized encodings based on varying assumptions, ranging from one-way functions to compact functional encryption.