IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
27 July 2016
Mohammad Mardani Shahrbabak, Shahab Abdolmaleky
Dana Dachman-Soled, S. Dov Gordon, Feng-Hao Liu, Adam O'Neill, Hong-Sheng Zhou
In the continual leakage model, a challenging problem has been to provide security against \emph{leakage on key updates}, that is, leakage that is a function not only of the current secret key but also the \emph{randomness used to update it}. We propose a new, modular approach to overcome this problem. Namely, we present a compiler that transforms any public-key encryption or signature scheme that achieves a slight strengthening of continual leakage resilience, which we call \emph{consecutive} continual leakage resilience, to one that is continual leakage resilient with leakage on key updates, assuming \emph{indistinguishability obfuscation} (Barak et al. --- CRYPTO 2001, Garg et al. -- FOCS 2013). Under the stronger assumption of \emph{public-coin differing-inputs obfuscation} (Ishai et al. -- TCC 2015) the leakage rate tolerated by our compiled scheme is essentially as good as that of the starting scheme. Our compiler is obtained by making a new connection between the problems of leakage on key updates and so-called ``sender-deniable'' encryption (Canetti et al. -- CRYPTO 1997), which was recently realized for the first time by Sahai and Waters (STOC 2014).
In the bounded leakage model, we develop a new approach to constructing leakage-resilient encryption from obfuscation, based upon the public-key encryption scheme from $\iO$ and punctured pseudorandom functions due to Sahai and Waters (STOC 2014). In particular, we achieve leakage-resilient public key encryption tolerating $L$ bits of leakage for any $L$ from $\iO$ and one-way functions. We build on this to achieve leakage-resilient public key encryption with optimal leakage rate of $1-o(1)$ based on public-coin differing-inputs obfuscation and collision-resistant hash functions. Such a leakage rate is not known to be achievable in a generic way based on public-key encryption alone. We then develop entirely new techniques to construct a new public key encryption scheme that is secure under (consecutive) continual leakage resilience (under appropriate assumptions), which we believe is of independent interest.
Herman Galteland, Stig F. Mjølsnes, Ruxandra F. Olimid
Raphael Bost
Yuqing Zhu, Jincheng Zhuang, Chang Lv, Dongdai Lin
In this paper, we devise a method to improve the individual logarithm step by exploring certain subfield structure. Our technique is based on the extended tower number field sieve method and generalizes the idea used by Guillevic. The method achieves more significant improvement when the extension degree has a large proper factor. We also perform some experiments to illustrate our algorithm and confirm the result.
Oriol Farràs, Jordi Ribes-González, Sara Ricci
Mustafa Khairallah, Maged Ghoneima
Frederik Armknecht, Jens-Matthias Bohli, David Froelicher, Ghassan O. Karame
Marc Fischlin, Anja Lehmann, Krzysztof Pietrzak
We therefore put forward the notion of robust multi-property combiners and elaborate on different definitions for such combiners. We then propose a combiner that provably preserves (target) collision-resistance, pseudorandomness, and being a secure message authentication code. This combiner satisfies the strongest notion we propose, which requires that the combined function satisfies every security property which is satisfied by at least one of the underlying hash function. If the underlying hash functions have output length n, the combiner has output length 2n. This basically matches a known lower bound for black-box combiners for collision-resistance only, thus the other properties can be achieved without penalizing the length of the hash values. We then propose a combiner which also preserves the property of being indifferentiable from a random oracle, slightly increasing the output length to 2n + \omega(log n). Moreover, we show how to augment our constructions in order to make them also robust for the one-wayness property, but in this case require an a priory upper bound on the input length.
26 July 2016
Center for IT-Security, Privacy, and Accountability, Saarland University, Saarbrücken, Germany
CISPA, the Center for IT-Security, Privacy, and Accountability at Saarland University in Germany is searching for excellent applicants with a strong international standing from all areas of IT Security, Privacy, and Cryptography.
Applicants are expected to display outstanding scientific research abilities, management skills, as well as excellent teaching skills and a strong dedication towards teaching. The scientific qualification should be especially proven by publications at the leading international IT-Security Conferences. University courses for Master’s studies and at the Graduate School are taught in English. The chosen applicant is expected to participate actively in the development of CISPA.
Closing date for applications: 12 August 2016
Contact: Prof. Dr. Michael Backes
Full Professor at Saarland University
Director of the Center for IT-Security, Privacy, and Accountability
Campus E 9 1, 66123 Saarbrücken, Germany
Email: backes (at) cispa.saarland
Phone: +49 681 302-3249
More information: https://www.cispa.saarland/education/careers/faculty-W1107/
Friedrich-Alexander-University, Nuermberg
Postdocs applicants are expected to have a PhD in cryptography or related areas, excellence in research proven for example by publications in IACR conferences and workshops CRYPTO, EUROCRYPT, ASIACRYPT, TCC, PKC,... or IT security venues like IEEE S&P, ACM CCS, NDSS, USENIX Security,….
Postdoc applicants should contact Dominique Schröder at bewerbungen-inf13 (at) lists.cs.fau.de and send the common application material in a single PDF file (i.e., CV, names of three references, a brief statement of research interests and experience.)
Starting date is negotiable. We are offering an internationally competitive salary. Review of applications starts immediately until the position is filled.
Closing date for applications: 31 August 2016
Contact: Dominique Schröder
Old website: www.ca.cs.uni-saarland.de
25 July 2016
Yale University, Electrical Engineering
* FPGAs and Verilog or VHDL programming
* Altera hardware and IP cores knowledge is desired, but not required
* Cryptography
Closing date for applications: 31 December 2016
Contact: Jakub Szefer
More information: http://caslab.eng.yale.edu/joinourteam
21 July 2016
Hongik University, Korea
Please email with subject ‘Postdoc position’ statement of research, CV, recommendation letters or referees, and copies of 3 most significant publications to sohwang (at) hongik.ac.kr
Closing date for applications: 12 August 2016
Contact: Professor Seong Oun Hwang at sohwang (at) hongik.ac.kr
More information: http://shinan.hongik.ac.kr/~sohwang/index_e.htm
McMaster University, Hamilton, Ontario, Canada
The Department of Computing and Software at McMaster University in Hamilton, Ontario, Canada, invites applications for a 27-month postdoctoral researcher position in the area of post-quantum cryptography under the supervision of Dr. Douglas Stebila, to begin October 2016.
The successful applicant will have strong experience in one or more forms of post-quantum cryptography (lattice-based, code-based, isogenies, multivariate quadratic, or hash-based signatures). Applicants with either theoretical skills or practical implementation skills are welcome. Applicants must be cleared to graduate from their PhD program by the commencement of the position.
This research is part of a project whose overall goal is to develop practical post-quantum cryptography for the Internet and other applications, and is funded by an NSERC Discovery Accelerator Supplement award.
The researcher will be expected to teach one undergraduate course in each of the two years of the contract, and will have the opportunity to participate in the co-supervision of Masters or PhD students. There is also the potential to participate in industry collaborations.
McMaster University is one of Canada\'s top universities, ranked 4th in Canada and 96th in the world in the 2015 Academic Ranking of World Universities. Hamilton is Canada\'s 9th largest city and is located in the Greater Toronto Area, less than an hour to downtown Toronto by public transit. Hamilton is located along the Niagara escarpment, with more than 100 waterfalls in the city limits, and lots of outdoor activities in the many nearby parks and conservation areas.
Applications should include a CV, names of three references, and a brief statement of research interests and experience, and must be submitted online (http://www.workingatmcmaster.ca/careers/: Job ID # 9483).
Closing date for applications: 25 August 2016
Contact: Dr. Douglas Stebila (stebilad (at) mcmaster.ca)
More information: http://www.workingatmcmaster.ca/careers/
Eurocrypt 2017 will be held on April 30-May 4, 2017 in Paris at Maison de la Mutualité, which is located right in the center of Paris, within walking distance of Notre Dame. EuroS&P 2017 will also take place in Paris at the UPMC Jussieu Campus (about 10 minutes walk away) during April 26-28, which is right before EUROCRYPT 2017. The affiliated events will be organized jointly with EuroS&P on April 29-30, 2017, at the UPMC Jussieu Campus.
Proposals are solicited for affiliated events to be held in conjunction with EuroS&P and EUROCRYPT 2017. Each affiliated event provides a forum to address a specific topic at the forefront of security or cryptography research. This includes workshops, tutorials, etc. that can be annual events, one time events, or aperiodic.
Important Dates for Affiliated Events
Event proposal deadline: August 12, 2016
Acceptance notification: August 26, 2016
Affiliated event dates: April 29-30, 2017
Provided Services
The EuroS&P and EUROCRYPT organizers provide only the following services to associated events:
- Conference room with projector
- Coffee during 3 coffee breaks (8-9am, 10:30-11am, and 3:30-4:00pm)
- Registration (small, fixed fee, covering the rooms and coffee)
Required Information for Proposing Event
Filling in the form below requires the following information:
- Name and acronym of the event
- Main affiliation (EuroS&P or EUROCRYPT)
- Type of event (Workshop, Tutorial, etc.)
- Abstract and Target audience
- Expected number of participants (e.g. a range)
- Will the event have a public call for contributions
- Will the event have proceedings
- List of event organizers and Contact email
- Expected event duration (up to 2 days) and the preferred date
- Information about past event instances
- Any special requests or additional information
Please submit event proposals using the following web form: http://goo.gl/forms/6JUV5DsV4DGKGzLy1. Please direct any questions to eurocrypt2017@iacr.org
Li Lin, Wenling Wu
Lucas Kowalczyk, Tal Malkin, Jonathan Ullman, Mark Zhandry
We show that, under the same assumption, if either the number of queries or the data universe is of exponential size, then there is no differentially private algorithm that answers all the queries. Specifically, we prove that if one-way functions and indistinguishability obfuscation exist, then:
1) For every $n$, there is a family $Q$ of $\tilde{O}(n^7)$ queries on a data universe $X$ of size $2^d$ such that no $\poly(n,d)$ time differentially private algorithm takes a dataset $D \in X^n$ and outputs accurate answers to every query in $Q$.
2) For every $n$, there is a family $Q$ of $2^d$ queries on a data universe $X$ of size $\tilde{O}(n^7)$ such that no $\poly(n,d)$ time differentially private algorithm takes a dataset $D \in X^n$ and outputs accurate answers to every query in $Q$.
In both cases, the result is nearly quantitatively tight, since there is an efficient differentially private algorithm that answers $\tilde{\Omega}(n^2)$ queries on an exponential size data universe, and one that answers exponentially many queries on a data universe of size $\tilde{\Omega}(n^2)$.
Our proofs build on the connection between hardness results in differential privacy and traitor-tracing schemes (Dwork et al., STOC'09; Ullman, STOC'13). We prove our hardness result for a polynomial size query set (resp., data universe) by showing that they follow from the existence of a special type of traitor-tracing scheme with very short ciphertexts (resp., secret keys), but very weak security guarantees, and then constructing such a scheme.
Seung Geol Choi, Dana Dachman-Soled, Tal Malkin, Hoeteck Wee
Our construction departs from the oft-used paradigm of re-encrypting the same message with different keys and then proving consistency of encryption. Instead, we encrypt an encoding of the message; the encoding is based on an error-correcting code with certain properties of reconstruction and secrecy from partial views, satisfied, e.g., by a Reed-Solomon code.