IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
27 September 2020
University of St. Gallen, Switzerland
Research area: Research areas include but are not limited to:
- Verifiable computation
- Secure Multi Party Computation
- Privacy-preserving authentication
- Cryptographic primitives
- A MsC degree in Computer Science, Applied Mathematics or a relevant field;
- Strong mathematical and algorithmic CS background;
- Good skills in programming is beneficial;
- Excellent written and verbal communication skills in English
Starting date: Fall 2020 or by mutual agreement
Closing date for applications:
Contact: Katerina Mitrokotsa
More information: https://jobs.unisg.ch/offene-stellen/phd-position-in-information-security-and-cryptography-m-w-d/6366821b-4848-4217-90d2-78e6b1096162
IMDEA Software Institute, Madrid, Spain
The IMDEA Software Institute invites applications for tenure-track (Assistant Professor) positions. We are primarily interested in excellent candidates in Systems, including Distributed Systems, Embedded Systems, etc.; Data Science, including machine learning; Security and Privacy; Software Engineering>; and Cyber-Physical Systems. Exceptional candidates in other topics within the research areas of the Institute will also be considered. Tenured-level (Associate and Full Professor) applications are also welcome.
The primary mission of the IMDEA Software Institute is to perform research of excellence at the highest international level in the area of software development technologies. It is one of the highest ranked institutions worldwide in its main topic areas.
All positions require a doctoral degree in CS or closely related area, earned by the expected start date. Candidates for tenure-track positions will have shown exceptional promise in research and ability to work independently as well as collaboratively. Candidates for tenured positions must have an outstanding research record, recognized international stature, and demonstrated leadership. Experience in graduate student supervision is also valued at this level.
For full consideration, complete applications must be received by December 1, 2020 but will continue to be accepted until the positions are filled.
The institute is located in the vibrant area of Madrid, Spain. It offers an ideal working environment, combining the best aspects of a research center and a university department. The institute offers institutional funding and also encourages participation in national and international research projects. The working language at the institute is English.
Salaries at the Institute are internationally competitive, established on an individual basis, and include social security provisions, and in particular access to an excellent public health care system.
COVID Note: The Institute continues working and hiring, while strictly adopting all recommended hea
Closing date for applications:
Contact: hiring@software.imdea.org
More information: https://software.imdea.org/open_positions/call_for_faculty.html
Information Security Group, Royal Holloway, University of London, UK
The PDRA will work alongside Dr. Martin Albrecht, Dr. Rachel Player and other cryptographic researchers at Royal Holloway on topics in lattice-based cryptography. This post is part of the EU H2020 PROMETHEUS project (http://prometheuscrypt.gforge.inria.fr) for building privacy preserving systems from advanced lattice primitives. Our research focus within this project is on cryptanalysis and implementations, but applicants with a strong background in other areas such as protocol/primitive design are also encouraged to apply.
Closing date for applications:
Contact: Martin Albrecht
More information: https://martinralbrecht.wordpress.com/2020/06/26/postdoc-at-royal-holloway-on-lattice-based-cryptography-3/
University of Warsaw
We are looking for talented and motivated Post-docs to work on the ERC AdG project PROCONTRA: Smart-Contract Protocols: Theory for Applications. The project is about theoretical and applied aspects of blockchain and smart contracts.
The ideal candidates should have a PhD degree in cryptography (or related field) from a leading university, and a proven record of publications in top cryptography/security/TCS venues.
We offer competitive salary, a budget for conference travel and research visit, and membership in a young and vibrant team with several international contacts (for more see: www.crypto.edu.pl).
A successful candidate will be given a substantial academic freedom and can work on a variety of research problems related to the main theme of the project.
There is no specific deadline for this call, but we will start looking at the applications from Oct 15th, 2020.
Closing date for applications:
Contact: Stefan Dziembowski
More information: https://www.crypto.edu.pl/positions
CISPA − Helmholtz Center for Information Security
What we are always looking for?
CISPA constantly seeks applications from outstanding students regardless of their national origin or citizenship. Currently we are looking for students interested in applied cryptography and topics like:
- privacy-preserving signatures,
- anonymous credentials,
- eID and ePassport security.
Admission to the Computer Science graduate program is highly competitive. A successful Master’s degree from a top-tier, research-oriented institution of higher education in a subject relevant to our research is required. Applicants should have an outstanding academic record, proficiency in spoken and written English, and strong letters of recommendation from their academic advisors.
What we offer?
CISPA maintains an open, international and diverse work environment. Every Ph.D. student is a member of a research group lead by his or her supervisor. Admitted students are as a rule paid employees of CISPA with a full time contract (TV-L E 13). The working language is English.
How to apply?
https://jobs.cispa.saarland/jobs/detail/phd-students-in-all-areas-related-to-cybersecurity-privacy-cryptography-and-machine-learning-1
Closing date for applications:
Contact: Lucjan Hanzlik (hanzlik@cispa.saarland)
More information: https://jobs.cispa.saarland/jobs/detail/phd-students-in-all-areas-related-to-cybersecurity-privacy-cryptography-and-machine-learning-1
University of St. Gallen, Switzerland
The position has an attractive salary and located in beautiful St. Gallen and Switzerland.
Research area: Research areas include but are not limited to:
- Verifiable computation
- Secure Multi Party Computation
- Privacy-preserving authentication
- Cryptographic primitives
- A PhD degree in Cryptography, information security;
- Strong mathematical and algorithmic CS background;
- Strong publication record;
- Good skills in programming is beneficial;
- Excellent written and verbal communication skills in English
Starting date: Fall 2020 or by mutual agreement
How to apply Submit your application through the online application system
Closing date for applications:
Contact: Katerina Mitrokotsa
More information: https://jobs.unisg.ch/offene-stellen/postdoc-fellow-in-cryptography-information-security/707c8a38-0c75-436e-b1b2-4ee6629d1323
EMSEC, University of Rennes 1, Rennes, France
- security proofs for lattice-based schemes,
- building and implementing lattice-based constructions,
- cryptanalysis and side channels attacks.
To apply please send us by email your detailed CV (with publication list). The positions has flexible starting date. Review of applications will start immediately until the positions are filled.
Closing date for applications:
Contact: Adeline Roux-Langlois / adeline.roux-langlois@irisa.fr
Protocol Labs
Closing date for applications:
Contact: Ed Burns
More information: https://jobs.lever.co/protocol/45adb8e8-4f5b-4da5-9c25-d1b84f3792e9
University of Maryland
- Post-quantum (including lattice-based) zero-knowledge proofs.
- Fast implementation of fully homomorphic encryption and lattice-based cryptography.
- Adversarial machine learning, broadly defined
Closing date for applications:
Contact: Jonathan Katz
25 September 2020
Rami Khalil, Naranker Dulay
David Heath, Vladimir Kolesnikov, Stanislav Peceny
The Goldreich-Micali-Wigderson, or GMW, protocol is a foundational circuit-based technique that realizes MPC for p players and is secure against up to p - 1 semi-honest corruptions. While GMW requires communication rounds proportional to the computed circuits depth, it is effective in many natural settings.
Our main contribution is MOTIF (Minimizing OTs for IFs), a novel GMW extension that evaluates conditional branches almost for free by amortizing Oblivious Transfers (OTs) across branches. That is, we simultaneously evaluate multiple independent AND gates, one gate from each mutually exclusive branch, by representing them as a single cheap vector-scalar multiplication (VS) gate.
For 2PC with b branches, we simultaneously evaluate up to b AND gates using only two 1-out-of-2 OTs of b-bit secrets. This is a factor ~b improvement over the state-of-the-art 2b 1-out-of-2 OTs of 1-bit secrets. Our factor b improvement generalizes to the multiparty setting as well: b AND gates consume only p(p - 1) 1-out-of-2 OTs of b-bit secrets.
We implemented our approach and report its performance. For 2PC and a circuit with 16 branches, each comparing two length-65000 bitstrings, MOTIF outperforms standard GMW in terms of communication by ~9.4x. Total wall-clock time is improved by 4.1 - 9.2x depending on network settings.
Our work is in the semi-honest model, tolerating all-but-one corruptions.
Chloe Cachet, Luke Demarest, Benjamin Fuller, Ariel Hamlin
This work builds searchable encryption that supports proximity queries for the Hamming metric. The Hamming metric is frequently used for the iris biometric. Searchable encryption schemes have leakage, which is information revealed to the database server such as identifiers of records returned which is known as access pattern leakage.
Prior work on proximity searchable encryption falls into two classes: 1) Li et al. (INFOCOM 2010) and Boldyreva and Chenette (FSE 2014) support only a polynomial number of close values, 2) Kim et al. (SCN 2018) leak the distance between the query and all stored records. The first class is not feasible due to the exponential number of close values. The second class allows the server to compute geometry of the space, enabling attacks akin to those on nearest neighbor schemes (Kornaropoulos et al. IEEE S&P 2019, 2020).
We build proximity search out of a new variant of inner product encryption called multi-point inner product encryption (MPIPE). MPIPE is built from function-hiding, secret-key, inner product predicate encryption (Shen, Shi, and Waters, TCC 2009). Our construction leaks access pattern and when two database records are the same distance from the queried point.
In most applications of searchable encryption the data distribution is not known a priori, making it prudent to consider leakage in a variety of settings. However, biometrics' statistics are well studied and static. Frequently in biometric search at most one record is returned. In this setting, access pattern leakage and the additional leakage of distance equality is unlikely to be harmful.
We also introduce a technique for reducing key size of a class of inner product encryption schemes based on dual pairing vector spaces. Our technique splits these vector spaces into multiple, smaller components, yielding keys that are a linear number of group elements instead of quadratic. We instantiate this technique on the scheme of Okamoto and Takashima (Eurocrypt, 2012) and show security under the same assumption (decisional linear).
Ryo Nishimaki
In this work, we present a general framework to equip a broad class of PKC primitives with an efficient watermarking scheme. The class consists of PKC primitives that have a canonical all-but-one (ABO) reduction. Canonical ABO reductions are standard techniques to prove selective security of PKC primitives, where adversaries must commit a target attribute at the beginning of the security game. Thus, we can obtain watermarking schemes for many existing efficient PKC schemes from standard cryptographic assumptions via our framework. Most well-known selectively secure PKC schemes have canonical ABO reductions. Notably, we can achieve watermarking for public-key encryption whose ciphertexts and secret-keys are constant-size, and that is chosen-ciphertext secure.
Our approach accommodates the canonical ABO reduction technique to the puncturable pseudorandom function (PRF) technique, which is used to achieve watermarkable PRFs. We find that canonical ABO reductions are compatible with such puncturable PRF-based watermarking schemes.
Zi-Yuan Liu, Yi-Fan Tseng, Raylin Tso
Alexander Bienstock, Yevgeniy Dodis, Paul Rösler
In this work we formally study the trade-off between PCS, concurrency, and communication overhead in the context of group ratcheting. Since our main result is a lower bound, we define the cleanest and most restrictive setting where the tension already occurs: static groups equipped with a synchronous (and authenticated) broadcast channel, where up to $t$ arbitrary parties can concurrently send messages in any given round. Already in this setting, we show in a symbolic execution model that PCS requires $\Omega(t)$ communication overhead per message. Our symbolic model permits as building blocks black-box use of (even "dual") PRFs, (even key-updatable) PKE (with functionality and security of HIBE), and broadcast encryption, capturing all tools used in previous constructions, but prohibiting the use of exotic primitives.
To complement our result, we also prove an almost matching upper bound of $\mathcal{O}(t\cdot(1+\log(n/t)))$, which smoothly increases from $\mathcal{O}(\log n)$ with no concurrency, to $\mathcal{O}(n)$ with unbounded concurrency, matching the previously known protocols.
Bar Alon, Ran Cohen, Eran Omri, Tom Suad
Our goal is to characterize the set of functionalities that can be computed with full security, assuming an honest majority, but no broadcast. This question was fully answered by Cohen et al. (TCC'16) -- for the restricted class of symmetric functionalities (where all parties receive the same output). Instructively, their results crucially rely on agreement and do not carry over to general asymmetric functionalities. In this work, we focus on the case of three-party asymmetric functionalities, providing a variety of necessary and sufficient conditions to enable fully secure computation.
An interesting use-case of our results is server-aided computation, where an untrusted server helps two parties to carry out their computation. We show that without a broadcast assumption, the resource of an external non-colluding server provides no additional power. Namely, a functionality can be computed with the help of the server if and only if it can be computed without it. For fair coin tossing, we further show that the optimal bias for three-party (server-aided) $r$-round protocol remains $\Theta(1/r)}$ (as in the two-party setting).
Sigurd Eskeland
Zvika Brakerski, Sanjam Garg, Rotem Tsabary
Our construction improves upon the prior construction of lattice-based DP-NIZK by Kim and Wu (Crypto 2018) since we only require leveled FHE as opposed to HS (which also translates to improved LWE parameters when instantiated). Alternatively, the recent construction of NIZK without preprocessing from either circular-secure FHE (Canetti et al., STOC 2019) or polynomial Learning with Errors (Peikert and Shiehian, Crypto 2019) could be used to obtain a similar final statement. Nevertheless, we note that our statement is formally incomparable to these works (since leveled FHE is not known to imply circular secure FHE or the hardness of LWE). We view this as evidence for the potential in our technique, which we hope can find additional applications in future works.
Inbar Kaslasi, Guy N. Rothblum, Ron D. Rothblum, Adam Sealfon, Prashant Nalini Vasudevan
Suppose, however, that the prover wishes to convince the verifier that $k$ separate inputs $x_1,\dots,x_k$ all belong to $\Pi$ (without revealing anything else). A naive way of doing so is to simply run the SZK protocol separately for each input. In this work we ask whether one can do better -- that is, is efficient batch verification possible for SZK?
We give a partial positive answer to this question by constructing a batch verification protocol for a natural and important subclass of SZK -- all problems $\Pi$ that have a non-interactive SZK protocol (in the common random string model). More specifically, we show that, for every such problem $\Pi$, there exists an honest-verifier SZK protocol for batch verification of $k$ instances, with communication complexity $poly(n) + k \cdot poly(\log{n},\log{k})$, where $poly$ refers to a fixed polynomial that depends only on $\Pi$ (and not on $k$). This result should be contrasted with the naive solution, which has communication complexity $k \cdot poly(n)$.
Our proof leverages a new NISZK-complete problem, called Approximate Injectivity, that we find to be of independent interest. The goal in this problem is to distinguish circuits that are nearly injective, from those that are non-injective on almost all inputs.