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21 December 2021
Shang GAO, Tianyu ZHENG, Yu GUO, Bin XIAO
Noga Ron-Zewi, Ron D. Rothblum
In this work we address this problem by constructing succinct arguments for general computations, expressed as Boolean circuits (of bounded fan-in), with a \emph{strictly linear} size prover. The soundness error of the protocol is an arbitrarily small constant. Prior to this work, succinct arguments were known with a \emph{quasi-}linear size prover for general Boolean circuits or with linear-size only for arithmetic circuits, defined over large finite fields.
In more detail, for every Boolean circuit $C=C(x,w)$, we construct an $O(\log |C|)$-round argument-system in which the prover can be implemented by a size $O(|C|)$ Boolean circuit (given as input both the instance $x$ and the witness $w$), with arbitrarily small constant soundness error and using $poly(\lambda,\log |C|)$ communication, where $\lambda$ denotes the security parameter. The verifier can be implemented by a size $O(|x|) + poly(\lambda, \log |C|)$ circuit following a size $O(|C|)$ private pre-processing step, or, alternatively, by using a purely public-coin protocol (with no pre-processing) with a size $O(|C|)$ verifier. The protocol can be made zero-knowledge using standard techniques (and with similar parameters). The soundness of our protocol is computational and relies on the existence of collision resistant hash functions that can be computed by linear-size circuits, such as those proposed by Applebaum et al. (ITCS, 2017).
At the heart of our construction is a new information-theoretic \emph{interactive oracle proof} (IOP), an interactive analog of a PCP, for circuit satisfiability, with constant prover overhead. The improved efficiency of our IOP is obtained by bypassing a barrier faced by prior IOP constructions, which needed to (either explicitly or implicitly) encode the entire computation using a multiplication code.
Matteo Campanelli, Dario Fiore, Semin Han, Jihye Kim, Dimitris Kolonelos, Hyunok Oh
Sonia Belaïd, Darius Mercadier, Matthieu Rivain, Abdul Rahman Taleb
Alessio Caminata, Michela Ceria, Elisa Gorla
Kaoutar Elkhiyaoui, Angelo De Caro, Elli Androulaki
Weizhao Jin, Bhaskar Krishnamachari, Muhammad Naveed, Srivatsan Ravi, Eduard Sanou, Kwame-Lante Wright
20 December 2021
Trondheim, Norway, 29 May 2022
Submission deadline: 7 March 2022
Notification: 15 April 2022
Boston, USA, 5 July - 7 July 2022
Submission deadline: 10 January 2022
Brandenburgische Technische Universität
Junior Researcher / PhD Student, limited to 2 years, full time, with possibility for extension
Our chair performs research and teaching in the area of IT Security with a strong focus on Network Security and Online Privacy. Our goal is to advance the state of the art in research and to educate qualified computer scientists in the area of IT Security who are able to meet the challenges of the growing demand on securing IT Systems and provide data protection in various areas of our life and society. More information about us can be found at https://www.b-tu.de/en/fg-it-sicherheit.
Tasks:
Active research in the area of intrusion detection systems (IDS) for critical infrastructures, secure cyber-physical systems, and artificial intelligence / machine learning for traffic analysis.
Implementation and evaluation of new algorithms and methods.
Cooperation and knowledge transfer with industrial partners.
Publication of scientific results.
Assistance with teaching.
The employment takes place with the goal of doctoral graduation (obtaining a PhD degree). Requirements:
Master’s degree (or equivalent) in Computer Science or related disciplines.
Strong interest in IT security and/or networking and distributed systems.
Knowledge of at least one programming language (C++, Java, etc.) and one scripting language (Perl, Python, etc.) or strong willingness to quickly learn new programming languages.
Linux/Unix skills.
Knowledge of data mining, machine learning, statistics and result visualization concepts is of advantage.
Excellent working knowledge of English; German is of advantage
Excellent communication skills.
For more information about the vacant position please contact Prof. A. Panchenko (E-Mail: itsec-jobs.informatik@lists.b-tu.de).
We value diversity and therefore welcome all applications.
Closing date for applications:
Contact: Prof. Andriy Panchenko
More information: https://www.b-tu.de/en/fg-it-sicherheit
Indian Institute of Technology Hyderabad, India
Closing date for applications:
Contact: Dr. Antony Franklin, Associate Professor, Department of Computer Science and Engineering, Indian Institute of Technology Hyderabad, India.
More information: https://newslab.iith.ac.in/
University of Luxembourg
Closing date for applications:
Contact: Prof. Dr. Thomas Engel (admin-engel@uni.lu).
Boris Ryabko
Georg Fuchsbauer, Riddhi Ghosal, Nathan Hauke, Adam O'Neill
Based on a relation we prove between approximate DCP and approximate distance-preserving functions, we design our core approximate DCPE scheme we call Scale-And-Perturb ($\mathsf{SAP}$). The encryption algorithm of $\mathsf{SAP}$ processes data on-the-fly. To boost security, we also introduce two preprocessing techniques: (1) normalizing the plaintext distribution, and (2) shuffling, wherein the component-wise encrypted dataset is randomly permuted. We prove (under suitable restrictions) that $\mathsf{SAP}$ achieves an indistinguishability-based security notion we call Real-or-Replaced ($\mathsf{RoR}$). In particular, our $\mathsf{RoR}$ result implies that our scheme prevents membership inference attacks by Yeom et al. (CSF 2018). Moreover, we show for i.i.d. multivariate normal plaintexts, we get security against approximate frequency-finding attacks, the main line of attacks against property-preserving encryption. This follows from a one-wayness $(\mathsf{OW})$ analysis. Finally, carefully combining our $\mathsf{OW}$ and $\mathsf{RoR}$ results, we are able characterize bit-security of $\mathsf{SAP}$.
Our overall findings are that our scheme not only has superior bit-security to OPE but resists specific attacks that even ideal order-revealing encryption (Boneh et al., EUROCRYPT 2015) does not. This suggests it could be sufficient for certain ANN applications, a subject on which we encourage further study.
Qiqi Lai, Feng-Hao Liu, Zhedong Wang
To achieve this, we first identify a new fine-grained security notion for ABE -- partially adaptive/selective security, and instantiate this notion from LWE. Then, by using this notion, we design a new key compressing mechanism for identity-based/attributed-based weak hash proof system (IB/AB-wHPS) for various policy classes, achieving (1) succinct secret keys and (2) adaptive/selective security matching the existing non-leakage resilient lattice-based designs. Using the existing connection between weak hash proof system and leakage resilient encryption, the succinct-key IB/AB-wHPS can yield the desired leakage resilient IBE/ABE schemes with the optimal leakage rates in the relative leakage model. Finally, by further improving the prior analysis of the compatible locally computable extractors, we can achieve the optimal leakage rates in the BRM.
Shiduo Zhang, Yang Yu
In this work, we propose two new gadget sampling algorithms for arbitrary moduli. Our first algorithm is for gadget Gaussian sampling. It is simple and efficient. One distinguishing feature of our Gaussian sampler is that it does not need floating-point arithmetic, which makes it better compatible with constrained environments. Our second algorithm is for gadget subgaussian sampling. Compared with the existing algorithm, it is simpler, faster, and requires asymptotically less randomness. In addition, our subgaussian sampler achieves an almost equal quality for different practical parameters. Overall these two algorithms provide simpler options for gadget algorithms and enhance the practicality of the gadget toolkit.
Prabhanjan Ananth, Luowen Qian, Henry Yuen
We construct, assuming the existence of pseudorandom state generators that map a $\lambda$-bit seed to a $\omega(\log\lambda)$-qubit state, (a) statistically binding and computationally hiding commitments and (b) pseudo one-time encryption schemes. A consequence of (a) is that pseudorandom states are sufficient to construct maliciously secure multiparty computation protocols in the dishonest majority setting.
Our constructions are derived via a new notion called pseudorandom function-like states (PRFS), a generalization of pseudorandom states that parallels the classical notion of pseudorandom functions. Beyond the above two applications, we believe our notion can effectively replace pseudorandom functions in many other cryptographic applications.
Mihai-Zicu Mina, Emil Simion
Emma Dauterman, Mayank Rathee, Raluca Ada Popa, Ion Stoica
18 December 2021
Research & Development Group, Horizen Labs; Milano, Italy
Our Core Engineering Team is an innovative and collaborative group of researchers and software engineers who are dedicated to the design and development of world-class blockchain-based products. We are looking for a cryptographer, or applied cryptographer, to join our growing crypto team based in Milan, Italy. Currently, the team is developing a protocol suite for SNARK-based proof-composition, but its duties reach beyond that, developing privacy-enhancing solutions for our sidechain ecosystem.
Responsabilities- Design privacy-enhancing technology built on SNARK-based protocols
- Perform collaborative research and assist technical colleagues in their development work
- Participate in standards-setting
- Ph.D. in mathematics, computer science, or cryptography
- Solid foundations in zero-knowledge and cryptographic protocols
- Publications in acknowledged venues on applied or theoretical cryptography, preferably cryptographic protocols or PETs
- Strong problem-solving skills
- The ability to work in a team setting as well as autonomously
- Foundations in blockchain technology and experience in reading Rust are a plus
- A competitive salary plus pre-series A stock options
- Flexible working hours, including the possibility of remote working
- The opportunity to work with talented minds on challenging topics in this field, including the most recent advancements in zero-knowledge
- A nice and informal team setting to conduct research and development of high-quality open source solutions
If you are interested in this position, you might want to take a look at our recent publications (IACR eprints 2021/930, 2021/399, 2020/123) and our latest podcast on zeroknowledge.fm (Episode 178). For further questions, please contact the email below.
Closing date for applications:
Contact: recruiting@horizenlabs.io
More information: https://horizenlabs.io/careers/job/?gh_jid=4116067004