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10 April 2023
Okinawa Institute of Science and Technology - OIST, Okinawa, Japan
The Applied Cryptography Unit (https://groups.oist.jp/appcrypto) at the Okinawa Institute of Science and Technology (OIST) is seeking to hire up to four postdoctoral scholars in cryptography.
The Applied Cryptography Unit, led by Prof Carlos Cid, was established in 2022, to conduct research in the design and analysis of modern cryptographic primitives and schemes used to protect confidentiality and integrity of data, both in the classical and in the quantum settings. To forge and develop its research activities, we are now seeking to hire up to four outstanding post-doctoral researchers to work in the following topics: post-quantum / quantum cryptography (design and analysis), quantum cryptanalysis, post-quantum cryptographic techniques for privacy-preserving mechanisms.
The postdocs will be provided with funding and access to world-class facilities to pursue their research. The Unit aims to establish a highly collaborative environment, and we expect there will be several opportunities to work with other research groups at OIST, in Japan and overseas.
Submission DocumentsApplicants should prepare a single pdf file with:
- Cover letter, outlining the motivation for applying for the position, research interests, experience and qualifications of relevance for the position;
- CV with a list of publications;
- Names and contact information of two referees, one of which should be a previous employer.
and submit it at https://www.oist.jp/careers/postdoctoral-scholars-applied-cryptography-unit
Application Deadline:Applicants will be considered until the positions are filled, but submissions by 28 May 2023 will guarantee full consideration.
Closing date for applications:
Contact: Carlos Cid (carlos.cid@oist.jp)
More information: https://www.oist.jp/careers/postdoctoral-scholars-applied-cryptography-unit
SUTD, Singapore
We offer PhD scholarship on cybersecurity in general and CPS security in particular (especially on IoT and maritime). The candidates should have an excellent background (with Bachelor or Master degree and CGPA>80%) in mathematics or computer science/engineering. Acquaintance with cryptography and network/system security concepts as well as some programming skills is preferred. Interested candidates please send your CV to Prof. Jianying Zhou or Prof. Sudipta Chattopadhyay. Only short-listed candidates will be contacted for interview.
Closing date for applications:
Contact: Prof. Jianying Zhou [jianying_zhou@sutd.edu.sg] or Prof. Sudipta Chattopadhyay [sudipta_chattopadhyay@sutd.edu.sg]
More information: https://itrust.sutd.edu.sg/
EURECOM
Topic - Artificial Intelligence (AI) technologies can efficiently process large amounts of data, to help stakeholders improve their services and propose applications tailored to end-user needs. While the benefits of AI technologies for the society are manifold and range from personalized services to improved healthcare, their adoption remains unfortunately slow due to various obstacles among which the lack of trustworthiness. Indeed, the performance and robustness of AI technologies rely on the access to large datasets of good quality. Such datasets usually include privacy-sensitive information. In this context, Federated learning (FL) is emerging as a powerful paradigm to collaboratively train a machine-learning (ML) model among thousands or even millions of participants. FL inherently promises (some) privacy and governance guarantees for the clients because the training data never leaves the client’s premises. Nevertheless, the collaborative aggregation of models’ parameters can potentially expose clients' specific information, and opens up to security breaches with potential loss of privacy. The successful candidate will study, the privacy and security challenges associated with federated learning and design and evaluate scalable and efficient privacy-enhancing technologies for FL using advanced cryptographic techniques such as multi-key homomorphic encryption or multi-party computation.
Requirements - Applicants should hold a Master degree or equivalent in Computer Science or a closely related area with a strong background on cryptography. Some background in machine learning is appreciated.
The application requires, among other documents, a CV, a cover letter describing the applicant’s research interests, the contact details of 2/3 persons that can provide references about the candidate and the transcripts of courses taken at graduate (and optionally undergraduate) level.
Closing date for applications:
Contact: Applicants are invited to send their applications via e-mail under reference [PhD-FLP] to melek.onen@eurecom.fr
Dfns Labs
Dfns is a cybersecurity company that builds custody SaaS solutions for web3 apps. Dfns gives financial institutions and businesses—from fintechs to e-commerce sites—the freedom to own and transfer crypto using a battle-designed security infrastructure.
Job Description
Basic Qualifications
Additional Information
Closing date for applications:
Contact: Please send your CV to research-jobs@dfns.co
Contact Xianrui Meng (xm@dfns.co) and Jon Katz (jkatz@dfns.co) for more information.
Centre for Secure Information Technologies (CSIT), Queen’s University Belfast, UK
Research Fellows will have the opportunity to advance research in areas such as: threat intelligence and monitoring, ICS malware detection and network intrusion detection, device trust, hardware/embedded systems security, security and verification of AI and threat prediction and prevention.
The successful candidates must have obtained, or be about to obtain, a PhD in engineering or physical sciences. At least 3 years’ high quality research experience in cybersecurity, and/or machine learning/AI, as evidenced by a strong track record of publications in leading journals and conferences in relevant areas.
Closing Date: 17/04/2023
Closing date for applications:
Contact: Paul Miller (p.miller@qub.ac.uk)
More information: https://hrwebapp.qub.ac.uk/tlive_webrecruitment/wrd/run/ETREC107GF.open?VACANCY_ID=411415IzIk&WVID=6273090Lgx&LANG=USA
Aikata Aikata, Andrea Basso, Gaetan Cassiers, Ahmet Can Mert, Sujoy Sinha Roy
For demonstration, we used the proposed technique and instantiated masked multipliers for schoolbook as well as NTT-based polynomial multiplication. Both of these can utilize the compact multipliers used in the unmasked implementations. The schoolbook multiplication requires an extra polynomial accumulation along with the two polynomial multiplications for a first-order protected implementation. However, this cost is nothing compared to the area saved by utilizing the existing cheap multiplication units. We also extensively test the side-channel resistance of the proposed design through TVLA to guarantee its first-order security.
Atsunori Ichikawa, Ilan Komargodski, Koki Hamada, Ryo Kikuchi, Dai Ikarashi
We present new and improved 3-party DORAM protocols. For a logical memory of size $N$ and for each logical operation, our DORAM requires $O(\log N)$ local CPU computation steps. This is known to be asymptotically optimal. Our DORAM satisfies passive security in the honest majority setting. Our technique results with concretely-efficient protocols and does not use expensive cryptography (such as re-randomizable or homomorphic encryption). Specifically, our DORAM is 25X faster than the known most efficient DORAM in the same setting.
Lastly, we extend our technique to handle malicious attackers at the expense of using slightly larger blocks (i.e., $\omega(\log^2 N)$ vs. $\Omega(\log N)$). To the best of our knowledge, this is the first concretely-efficient maliciously secure DORAM.
Technically, our construction relies on a novel concretely-efficient 3-party oblivious permutation protocol. We combine it with efficient non-oblivious hashing techniques (i.e., Cuckoo hashing) to get a distributed oblivious hash table. From this, we build a full-fledged DORAM using a distributed variant of the hierarchical approach of Goldreich and Ostrovsky (J. ACM '96). These ideas, and especially the permutation protocol, are of independent interest.
Reyhaneh Rabaninejad, Behzad Abdolmaleki, Giulio Malavolta, Antonis Michalas, Amir Nabizadeh
Yuval Ishai, Dakshita Khurana, Amit Sahai, Akshayaram Srinivasan
We present the first reusable NISC protocol for general functions $f$ that only makes a {\em black-box} use of any two-message oblivious transfer protocol, along with a random oracle. All previous reusable NISC protocols either made a non-black-box use of cryptographic primitives (Cachin et al., ICALP 2002) or alternatively required a stronger arithmetic variant of oblivious transfer and were restricted to $f$ in $\mathsf{NC}^1$ or similar classes (Chase et al., Crypto 2019). Our result is obtained via a general compiler from standard NISC to reusable NISC that makes use of special type of honest-majority protocols for secure multiparty computation.
Finally, we extend the above main result to reusable {\em two-sided} NISC, in which two parties can encrypt their inputs in the first round and then reveal different functions of their inputs in multiple sessions. This extension either requires an additional (black-box) use of additively homomorphic commitment or alternatively requires the parties to maintain a state between sessions.
Elette Boyle, Geoffroy Couteau, Pierre Meyer
We develop new techniques expanding the set of computational assumptions for sublinear communication in both settings:
1) [Circuit size] We present sublinear-communication protocols for secure evaluation of general layered circuits, given any 2-round rate-1 batch oblivious transfer (OT) protocol with a particular ``decomposability'' property. In particular, this condition can be shown to hold for the recent batch OT protocols of (Brakerski et al. Eurocrypt 2022), in turn yielding a new sublinear secure computation feasibility result: from Quadratic Residuosity (QR) together with polynomial-noise-rate Learning Parity with Noise (LPN). Our approach constitutes a departure from existing paths toward sublinear secure computation, all based on fully homomorphic encryption or homomorphic secret sharing.
2) [Input size.] We construct single-server PIR based on the Computational Diffie-Hellman (CDH) assumption, with polylogarithmic communication in the database input size $n$. Previous constructions from CDH required communication $\Omega(n)$. In hindsight, our construction comprises of a relatively simple combination of existing tools from the literature.
Shankara Pailoor, Yanju Chen, Franklyn Wang, Clara Rodríguez, Jacob Van Gaffen, Jason Morton, Michael Chu, Brian Gu, Yu Feng, Isil Dillig
Motivated by this problem, we propose a new technique for finding ZKP bugs caused by underconstrained polynomial equations over finite fields. Our method performs semantic reasoning over the finite field equations generated by the compiler to prove whether or not each signal is uniquely determined by the input. Our proposed approach combines SMT solving with lightweight uniqueness inference to effectively reason about underconstrained circuits. We have implemented our proposed approach in a tool called $\mathbf{\mathsf{QED}^2}$ and evaluate it on 163 Circom circuits. Our evaluation shows that $\mathbf{\mathsf{QED}^2}$ can successfully solve 70\% of these benchmarks, meaning that it either verifies the uniqueness of the output signals or finds a pair of witnesses that demonstrate non-uniqueness of the circuit. Furthermore, $\mathbf{\mathsf{QED}^2}$ has found 8 previously unknown vulnerabilities in widely-used circuits.
Dimitris Mouris, Charles Gouert, Nektarios Georgios Tsoutsos
Anit Kumar Ghosal, Dipanwita Roychowdhury
Anit Kumar Ghosal, Dipanwita Roychowdhury
Jesús-Javier Chi-Domínguez, Amalia Pizarro-Madariaga, Edgardo Riquelme
This work presents a general framework that generalizes the situation of computing isogenies of the large-smooth degree to the context of quotient groups. More precisely, we abstract and propose a generalization of the strategy technique by Jao, De Feo, and Plût. Such a framework provides an efficient generic algorithm that easily applies to computing isogenies over superspecial PPAS when given the isogeny kernel. Additionally, our algorithm induces an efficient algorithm to perform the KernelToIsogeny procedure required in SQISignHD.
To illustrate the impact of optimal strategies, we draft our experiments on the isogenies over superspecial PPAS required in the Castryck-Decru attack (powers of two and three). Our experiments illustrate a decent speed up of 1.25x faster than the state-of-the-art (about 20% of savings). Our results should be viewed as proof-of-concept implementation and considered for optimized C-language implementations.
Jesús-Javier Chi-Domínguez, Andre Esser, Sabrina Kunzweiler, Alexander May
We use the recently introduced Restricted Effective Group Actions ($\mathsf{REGA}$) to illustrate the analogy between CSIDH and Diffie-Hellman key exchange. This framework allows us to introduce a $\mathsf{REGA}\text{-}\mathsf{DLOG}$ problem as a level of abstraction to computing isogenies between elliptic curves, analogous to the classic discrete logarithm problem. This in turn allows us to study $\mathsf{REGA}\text{-}\mathsf{DLOG}$ with ternary key spaces such as $\{-1, 0, 1\}^n, \{0,1,2\}^n$ and $\{-2,0,2\}^n$, which lead to especially efficient, recently proposed CSIDH instantiations. The best classic attack on these key spaces is a Meet-in-the-Middle algorithm that runs in time $3^{0.5 n}$, using also $3^{0.5 n}$ memory.
We first show that $\mathsf{REGA}\text{-}\mathsf{DLOG}$ with ternary key spaces $\{0,1,2\}^n$ or $\{-2,0,2\}^n$ can be reduced to the ternary key space $\{-1,0,1\}^n$.
We further provide a heuristic time-memory tradeoff for $\mathsf{REGA}\text{-}\mathsf{DLOG}$ with keyspace $\{-1,0,1\}^n$ based on Parallel Collision Search with memory requirement $M$ that under standard heuristics runs in time $3^{0.75 n}/M^{0.5}$ for all $M \leq 3^{n/2}$. We then use the representation technique to heuristically improve to $3^{0.675n}/M^{0.5}$ for all $M \leq 3^{0.22 n}$, and further provide more efficient time-memory tradeoffs for all $M \leq 3^{n/2}$.
Although we focus in this work on $\mathsf{REGA}\text{-}\mathsf{DLOG}$ with ternary key spaces for showing its efficacy in providing attractive time-memory tradeoffs, we also show how to use our framework to analyze larger key spaces $\{-m, \ldots, m\}^n$ with $m = 2,3$.
George Tasopoulos, Charis Dimopoulos, Apostolos P. Fournaris, Raymond K. Zhao, Amin Sakzad, Ron Steinfeld
Matthias Probst, Manuel Brosch, Georg Sigl
Shuailiang Hu
Based on Lagrangian interpolation polynomials, we propose a fully homomorphic encryption scheme according to the difficulty of finding roots of a polynomial with the degree of at least two(mod n=p*q, p, q are both private large primes). We reasonably construct polynomials $trap_1$ and $trap_0$ to generate the ciphertext of message m, so that calculation between ciphertexts can directly act on plaintexts. Our scheme is safe as long as the Rabin encryption algorithm cannot be cracked.