IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
26 September 2022
Yuval Ishai, Arpita Patra, Sikhar Patranabis, Divya Ravi, Akshayaram Srinivasan
-- For a natural class of protocols, specifically, those with a universal output decoder, we show that the size of the TP must necessarily be exponential in the number of parties. This result holds irrespective of the computational assumptions used in the protocol. The class of protocols to which our lower bound applies is broad enough to capture prior results in the area, implying that the prior techniques necessitate the use of an exponential-sized TP. We additionally rule out the possibility of achieving information-theoretic full security (without the restriction of using a universal output decoder) using a “small” TP in the plain model (i.e., without any setup).
-- In order to get around the above negative result, we consider protocols without a universal output decoder. The main positive result in our work is a construction of such a fully-secure MPC protocol assuming the existence of a succinct Functional Encryption scheme. We also give evidence that such an assumption is likely to be necessary for fully-secure MPC in certain restricted settings.
-- Finally, we explore the possibility of achieving full-security with a semi-honest TP that could collude with other malicious parties (which form a dishonest majority). In this setting, we show that even fairness is impossible to achieve regardless of the “small TP” requirement.
Trevor Yap, Adrien Benamira, Shivam Bhasin, Thomas Peyrin
University of St.Gallen, Switzerland
The student is expected to work on topics that include security and privacy issues in biometric authentication. More precisely, the student will be working on investigating efficient and privacy-preserving authentication that provides: i) provable security guarantees, and ii) rigorous privacy guarantees.
Key Responsibilities:
- Perform exciting and challenging research in the domain of information security and cryptography.
- Support and assist in teaching computer security and cryptography courses.
- The PhD student is expected to have a MSc degree or equivalent, and strong background in cryptography, network security and mathematics.
- Experience in one or more domains such as cryptography, design of protocols, secure multi-party computation and differential privacy is beneficial.
- Excellent programming skills.
- Excellent written and verbal communication skills in English
Please apply by 15th October 2022.
Closing date for applications:
Contact:
Eriane Breu, eriane.breu@unisg.ch (Administrative matters)
Prof. Katerina Mitrokotsa, katerina.mitrokotsa@unisg.ch (Research related questions)
IHUB NTIHAC FOUNDATION, IIT Kanpur, Kanpur-208016, U.P., INDIA
Closing date for applications:
Contact: Submissions are accepted only through an email to Professor Manindra Agrawal (manindra@cse.iitk.ac.in), Director, C3iHub, IIT Kanpur.
More information: https://www.linkedin.com/jobs/view/cryptanalyst-at-c3i-hub-3243352185/?originalSubdomain=in
24 September 2022
Okinawa Institute of Science and Technology Graduate University
The Okinawa Institute of Science and Technology (OIST) is a dynamic and growing graduate university in Japan. We are inviting applications for tenure-track and tenured faculty positions in the areas of Quantum Information Science and Quantum Technology, Applied Cryptography and Cyber Security.
Successful candidates will have an opportunity to join our vibrant, collaborative, interdisciplinary research community. They will:
- establish and run an active independent Research Unit with generous internal funding, including funds for several research staff;
- supervise and mentor PhD students, develop and teach graduate courses, and actively contribute to university services;
- receive access to cutting-edge core research facilities, including imaging, sequencing, instrumentation, nanofabrication, and high-performance computing, with dedicated support staff;
- enjoy a competitive remuneration package with additional benefits, such as housing allowance.
OIST is actively seeking applications from women and underrepresented groups.
Deadline for applications: 30 Nov 2022 at 12:59 PM JST.
About OIST
OIST is a dynamic and growing graduate university in Japan, offering a world-class research environment and opportunities for cross-disciplinary research. We have no departments, and we currently have 89 Research Units. English is the official language of the university, and the research community is fully international, with more than 50 countries represented. The campus is located on 85 hectares of protected forestland overlooking beautiful shorelines and coral reefs in subtropical Okinawa, Japan. To learn more about OIST, visit www.oist.jp
Closing date for applications:
Contact: Dr. Milind Purohit, Dean of Faculty Affairs (faculty-recruiting at oist.jp)
More information: https://groups.oist.jp/facultypositions
National University of Singapore
Closing date for applications:
Contact: Faculty search committee chair Prof. Joxan Jaffar (joxan@comp.nus.edu.sg) Head, Prof. Lee Wee Sun (leews@comp.nus.edu.sg)
More information: https://www.comp.nus.edu.sg/images/resources/content/dept-compscience/20210923_DCS_Poster_v4.pdf
Lund University
Closing date for applications:
Contact: Prof. Christian Gehrmann
More information: https://lu.varbi.com/en/what:job/jobID:543355/type:job/where:4/apply:1
University of South Florida, The Department of Computer Science and Engineering, Tampa, FL, USA.
USF is a Rank-1 Research University, and USF CSE is top 15% among Computer Science departments in public universities based on Academic Analytics data based on Scholarly Research Index (and top 8th for patents in the USA). USF offers an excellent working environment, all within proximity to high-tech industry and the beautiful beaches of sunny Florida. Tampa/Orlando area is in Florida High Technology Corridor and harbors major tech and research companies. The qualified candidate will have opportunities for research internships in lead-industrial companies. Topics include:
Trustworthy Machine Learning (TML)
- Privacy-Preserving Machine Learning
- Secure multi-party computation for TML
- New cryptographic schemes for consensus and distributed transactions in Blockchains
- Practical quantum-safe cryptographic deployments for Blockchains
- Lightweight cryptography for IoT
- Efficient cryptography for vehicular and unmanned aerial systems
- Searchable encryption, Oblivious RAM, and multi-party computation
- A BS degree in ECE/CS with a high-GPA
- Very good programming skills (e.g., C, C++), familiarity with Linux
-
MS degree in ECE/CS/Math is a big plus. Publications will be regarded as a plus but not required.
Closing date for applications:
Contact: Associate Prof. Dr. Attila A. Yavuz
Email: attilaayavuz@usf.edu
Email: attila.yavuz@gmail.com
Webpage : http://www.csee.usf.edu/~attilaayavuz/More information: https://cse.usf.edu/~attilaayavuz/Recruiting/[FallSpring2023]PositionDescrption_at_USF.pdf
Nation Towers, Tower A, United Arab Emirates, 13 November - 16 November 2022
23 September 2022
Jie Chen, Yu Li, Jinming Wen, Jian Weng
More concretely, our IB-ME is constructed from a variant of two-level anonymous IBE. We observed that this two-level IBE with anonymity and unforgeability satisfies the same functionality of IB-ME, and its security properties cleverly meet the two requirements of IB-ME (Privacy and Authenticity). The privacy property of IB-ME relies on the anonymity of this two-level IBE, while the authenticity property is corresponding to the unforgeability in the 2nd level. This variant of two-level IBE is built from dual pairing vector spaces, and both security reductions rely on dual system encryption.
Lorenzo Grassi
19 September 2022
Yu Long Chen
We also present a framework to use the new techniques, which provides the bad events that need to be excluded in order to apply the public permutation mirror theory. Furthermore, we showcase the new technique on three examples: the Tweakable Even-Mansour cipher by Cogliati et al. (CRYPTO ’15), the two permutation variant of the pEDM PRF by Dutta et al. (ToSC ’21(2)), and the two permutation variant of the nEHtM\(_p\) MAC algorithm by Dutta and Nandi (AFRICACRYPT ’20). With this new tool we prove the multi-user security of these constructions in a considerably simplified way.
Hanno Becker, Matthias J. Kannwischer
Amos Treiber, Dirk Müllmann, Thomas Schneider, Indra Spiecker genannt Döhmann
Secure Multi-Party Computation (MPC) is often seen as a technological means to solve privacy conflicts where actors want to exchange and analyze data that needs to be protected due to data protection laws. In this interdisciplinary work, we investigate the problem of private information exchange between LEAs from both a legal and technical angle. We give a legal analysis of secret-sharing based MPC techniques in general and, as a particular application scenario, consider the case of matching LE databases for lawful information exchange between LEAs. We propose a system for lawful information exchange between LEAs using MPC and private set intersection and show its feasibility by giving a legal analysis for data protection and a technical analysis for workload complexity. Towards practicality, we present insights from qualitative feedback gathered within exchanges with a major European LEA.
George Teseleanu, Paul Cotan
George Teseleanu
Jun Xu, Santanu Sarkar, Huaxiong Wang, Lei Hu
In this paper, we revisit the Coppersmith method for solving the involved modular multivariate polynomials in the Diffie--Hellman variant of EC-HNP and demonstrate that, for any given positive integer $d$, a given sufficiently large prime $p$, and a fixed elliptic curve over the prime field $\mathbb{F}_p$, if there is an oracle that outputs about $\frac{1}{d+1}$ of the most (least) significant bits of the $x$-coordinate of the ECDH key, then one can give a heuristic algorithm to compute all the bits within polynomial time in $\log_2 p$. When $d>1$, the heuristic result $\frac{1}{d+1}$ significantly outperforms both the rigorous bound $\frac{5}{6}$ and heuristic bound $\frac{1}{2}$. Due to the heuristics involved in the Coppersmith method, we do not get the ECDH bit security on a fixed curve. However, we experimentally verify the effectiveness of the heuristics on NIST curves for small dimension lattices.
Ping Wang, Yiting Su, Fangguo Zhang
Alexander Bienstock, Yevgeniy Dodis, Sanjam Garg, Garrison Grogan, Mohammad Hajiabadi, Paul Rösler
1. Can we have CGKA protocols that are efficient in the worst case? We start by answering this basic question in the negative. First, we show that a natural primitive that we call Compact Key Exchange (CKE) is at the core of CGKA, and thus tightly captures CGKA's worst-case communication cost. Intuitively, CKE requires that: first, $n$ users non-interactively generate key pairs and broadcast their public keys, then, some other special user securely communicates to these $n$ users a shared key. Next, we show that CKE with communication cost $o(n)$ by the special user cannot be realized in a black-box manner from public-key encryption, thus implying the same for CGKA, where $n$ is the corresponding number of group members. Surprisingly, this impossibility holds even in an offline setting, where parties have access to the sequence of group operations in advance.
2. Can we realize one CGKA protocol that works as well as possible in all cases? Here again, we present negative evidence showing that no such protocol based on black-box use of public-key encryption exists. Specifically, we show two distributions over sequences of group operations such that no CGKA protocol obtains optimal communication costs on both sequences.
Lalita Devadas, Rishab Goyal, Yael Kalai, Vinod Vaikuntanathan
In contrast, prior work either relied on non-standard knowledge assumptions, or produced proofs of size $m \cdot \mathsf{poly}(\lambda,\log k)$ (Choudhuri, Jain, and Jin, STOC 2021, following Kalai, Paneth, and Yang 2019). We show how to use our rate-$1$ BARG scheme to obtain the following results, all under the LWE assumption: - A multi-hop BARG scheme for $\mathsf{NP}$. - A multi-hop aggregate signature scheme (in the standard model). - An incrementally verifiable computation (IVC) scheme for arbitrary $T$-time deterministic computations with proof size $\mathsf{poly}(\lambda,\log T)$. Prior to this work, multi-hop BARGs were only known under non-standard knowledge assumptions or in the random oracle model; aggregate signatures were only known under indistinguishability obfuscation (and RSA) or in the random oracle model; IVC schemes with proofs of size $\mathsf{poly}(\lambda,T^{\epsilon})$ were known under a bilinear map assumption, and with proofs of size $\mathsf{poly}(\lambda,\log T)$ under non-standard knowledge assumptions or in the random oracle model.