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14 January 2022
Atakan Arslan, Muhammed Ali Bingöl
ePrint ReportKonstantinos Chalkias, Panagiotis Chatzigiannis, Yan Ji
ePrint ReportAMBILI K N, JIMMY JOSE
ePrint ReportAMBILI K N, JIMMY JOSE
ePrint ReportAMBILI K N, JIMMY JOSE
ePrint ReportAMBILI K N, JIMMY JOSE
ePrint ReportAntonio de la Piedra, Marloes Venema, Greg Alpár
ePrint ReportIn this work, we present a framework for accurately benchmarking efficiency of ABE: ABE Squared. In particular, we focus on uncovering the multiple layers of optimization that are relevant to the implementation of ABE schemes. Moreover, we focus on making any comparison fairer by considering the influence of the potential design goals any optimizations. On the lowest layer, we consider the available optimized arithmetic provided by state-of-the-art cryptographic libraries. On the higher layers, we consider the choice of elliptic curve, the order of the computations, and the instantiation of the scheme on the chosen curves. In this latter aspect, the way in which a scheme is type converted plays an important role. Additionally, we show that especially the higher-level optimizations are dependent on the goal of the designer, e.g. optimization of the decryption algorithm. To compare schemes more transparently, we develop this framework, in which ABE schemes can be justifiably optimized and compared by taking into account the possible goals of a designer. To meet these goals, we also introduce manual, heuristic type-conversion techniques where existing techniques fall short. Finally, to illustrate the effectiveness of ABE Squared, we implement several schemes and provide all relevant benchmarks. These show that the design goal influences the optimization approaches, which in turn influence the overall efficiency of the implementations. Importantly, these show that the schemes also compare differently than existing works previously suggested.
Dmitrii Koshelev
ePrint ReportMelissa Azouaoui, Olivier Bronchain, Clément Hoffmann, Yulia Kuzovkova, Tobias Schneider, François-Xavier Standaert
ePrint ReportVipul Goyal, Justin Raizes, Pratik Soni
ePrint ReportWe study zero-knowledge and secure computation through the lens of a new security notion where the simulator is given the ability to ``time-travel” or more accurately, to look into the future states of the blockchain and use this information to perform simulation. Such a time-traveling simulator gives a novel security guarantee of the following form: whatever the adversary could have learnt from an interaction, it could have computed on its own shortly into the future (e.g., a few hours from now).
We exhibit the power of time-traveling simulators by constructing round-efficient protocols in the blockchain-hybrid model. In particular, we construct: 1. Three-round zero-knowledge (ZK) argument for NP with a polynomial-time black-box time-traveling simulator. 2. Three-round secure two-party computation (2PC) for any functionality with a polynomial-time black-box time-traveling simulator for both parties.
In addition to standard cryptographic assumptions, we rely on natural hardness assumptions for Proof-of-Work based blockchains. In comparison, in the plain model, three-round protocols with black-box simulation are impossible, and constructions with non-black-box simulation for ZK require novel cryptographic assumptions while no construction for three-round 2PC is known. Our three-round 2PC result relies on a new, two-round extractable commitment that admits a time-traveling extractor.
Varun Madathil, Chris Orsini, Alessandra Scafuro, Daniele Venturi
ePrint ReportJonathan Godin, Philippe Lamontagne
ePrint ReportThe main thesis of this paper is that deletion-compliance is a standalone notion, distinct from privacy. We present an alternative definition that meaningfully captures deletion-compliance without any privacy implications. This allows broader class of data collectors to demonstrate compliance to deletion requests and to be paired with various notions of privacy. Our new definition has several appealing properties: - It is implied by the stronger definition of Garg et al. under natural conditions, and is equivalent when we add a privacy requirement. - It is naturally composable with minimal assumptions. - Its requirements are met by data structure implementations that do not reveal the order of operations, a concept known as history-independence.
Along the way, we discuss the many challenges that remain in providing a universal definition of compliance to the "right to be forgotten."
Denis Firsov, Sven Laur, Ekaterina Zhuchko
ePrint ReportPierre-Alain Fouque, Paul Kirchner, Thomas Pornin, Yang Yu
ePrint ReportJinyu Lu, Guoqiang Liu, Yunwen Liu, Bing Sun, Chao Li, Li Liu
ePrint ReportUniversity of Tübingen, Department of Computer Science; Tübingen, Germany
Job PostingResearch Topics: Development and analysis of cryptography-based privacy-preserving solutions for real-world healthcare problems. Topics of interest include (but are not limited to): privacy-preserving machine learning, genomic privacy, medical privacy as well as foundations for real-world cryptography.
Your profile:
- Completed Master's degree (or equivalent) at a top university with excellent grades in computer science, or a similar area.
- Extensive knowledge in applied cryptography/security and machine learning.
- Very good software development skills.
- Knowledge of cryptographic protocols (ideally MPC).
- Knowledge of bioinformatics or genomics is plus.
- Self-motivated, reliable, creative, can work independently and want to do excellent research.
Closing date for applications:
Contact: Dr. Mete Akgün (mete.akguen@uni-tuebingen.de)
University of Innsbruck, Austria, EU
Job PostingThe University of Innsbruck, located in the heart of the alps, has a tenure track opportunity in the field of cryptography.
The Department of Computer Science is looking for an ambitious researcher to build a bridge between the interdisciplinary approach taken by its Security & Privacy Lab and theoretical research groups, like Computational Logic and Theoretical Computer Science. Research activities would focus on producing evidence on the security or privacy of cryptographic systems covering theory and/or implementation. The individual should be comfortable teaching multiple approaches to cryptography. The ideal candidate would build a research group on cryptography in the course of the tenure process, the details of which are negotiated in the first year of employment as routinely done in the Austrian academic system.
Tyrol, Austria is one of the most livable places in Europe with world-class healthcare, excellent social security, and free education from kindergarden to university.
Applications are due on 28 January 2022. Follow the link above for more details.
Closing date for applications:
Contact: Rainer Böhme [rainer dot boehme at uibk.ac.at]
More information: https://informationsecurity.uibk.ac.at/pdfs/vacancy_cryptography_2022.pdf
10 January 2022
Graz University of Technology, Graz, Austria
Job PostingIn order to complement our team, we are looking for a full-time PhD researcher in the implementation aspects of cryptography.
Responsibilities:
The PhD researcher will be working on Scientific research in the field of implementation and physical security aspects of novel cryptographic algorithms within the “Cyroptografic Engineering” group within the “Secure Systems” area at IAIK.
Required Qualifications:
How to apply: Applications, curriculum vitae and other documents should preferably be uploaded here csbme.tugraz.at/go/applications/7050-21-013.
The earliest starting date for the PhD candidate will be March 2022.
The application deadline is February 6th.
Closing date for applications:
Contact: Sujoy Sinha-Roy - sujoy.sinha-roy@iaik.tugraz.at
More information: https://www.tugraz.at/tu-graz/karriere/ausgeschriebene-jobs/ausgeschriebene-wissenschaftliche-stellen-ausser-professuren/#c427935
ADVA Optical Networking, Munich, Germany
Job PostingClosing date for applications:
Contact: Joo Yeon Cho (jcho@adva.com)
More information: https://adva.wd3.myworkdayjobs.com/en-US/ADVA/job/Munich-Germany/Engineer-Advanced-Technology--M-F-D-_R001000
Laboratoire Hubert Curien, University of Lyon, Saint-Etienne, France
Job PostingClosing date for applications:
Contact: Contact: Prof. Lilian BOSSUET lilian.bossuet(at)univ-st-etienne.fr