IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
19 September 2022
Tianshu Shan, Jiangxia Ge, Rui Xue
In this paper, we formalize one class of public-key encryption schemes, named oracle-masked schemes, relative to random oracles. For each oracle-masked scheme, we design a preimage extraction procedure and prove that it simulates the quantum decryption oracle with a certain loss. We also observe that the implementation of the preimage extraction procedure for some oracle-masked schemes does not need to take the secret key as input. This contributes to the IND-qCCA security proof of these schemes in the quantum random oracle model (QROM). As an application, we prove the IND-qCCA security of schemes obtained by the Fujisaki-Okamoto (FO) transformation and REACT transformation in the QROM, respectively.
Notably, our security reduction for FO transformation is tighter than the reduction given by Zhandry (Crypto 2019).
Soumya Chattopadhyay, Ashwin Jha, Mridul Nandi
Yevgeniy Dodis, Daniel Jost, Harish Karthikeyan
To address these inefficiencies, we look at the common real-life situation which we call the bulletin board model, where communicating parties rely on some infrastructure -- such as an application provider -- to help them store and deliver ciphertexts to each other. We then define and construct FF-FSE in the bulletin board model, which addresses the above-mentioned disadvantages. In particular,
* Our FF-stream-cipher in the bulletin-board model has: (a) constant state size; (b) constant normal (no fast-forward) operation; and (c) logarithmic fast-forward property. This essentially matches the efficiency of non-fast-forwardable stream ciphers, at the cost of constant communication complexity with the bulletin board per update.
* Our public-key FF-FSE avoids HIBE-based techniques by instead using so-called updatable public-key encryption (UPKE), introduced in several recent works (and more efficient than public-key FSEs). Our UPKE-based scheme uses a novel type of "update graph" that we construct in this work. Our graph has constant in-degree, logarithmic diameter, and logarithmic "cut property" which is essential for the efficiency of our schemes. Combined with recent UPKE schemes, we get two FF-FSEs in the bulletin board model, under the DDH and the LWE assumptions.
Julia Kastner, Julian Loss, Jiayu Xu
We point out several subtle flaws in the original proof of security, and provide a new detailed and rigorous proof, achieving similar bounds as the original work. We believe our insights on the proof strategy will find useful in the security analyses of other OR-proof-based schemes.
Gianluca Brian, Sebastian Faust, Elena Micheli, Daniele Venturi
Julien Duman, Dominik Hartmann, Eike Kiltz, Sabrina Kunzweiler, Jonas Lehmann, Doreen Riepel
We prove that active security of the two protocols in the Quantum Random Oracle Model (QROM) inherently relies on very strong variants of the Group Action Strong CDH problem, where the adversary is given arbitrary quantum access to a DDH oracle. That is, quantum accessible Strong CDH assumptions are not only sufficient but also necessary to prove active security of the GA-HEG KEM and the GA-HDH NIKE protocols.
Furthermore, we propose variants of the protocols with QROM security from the classical Strong CDH assumption, i.e., CDH with classical access to the DDH oracle. Our first variant uses key confirmation and can therefore only be applied in the KEM setting. Our second but considerably less efficient variant is based on the twinning technique by Cash et al. (EUROCRYPT '08) and in particular yields the first actively secure isogeny-based NIKE with QROM security from the standard CDH assumption.
18 September 2022
Bol, Croatia, 1 May - 5 May 2023
Submission deadline: 19 October 2022
Notification: 19 January 2023
SUTD, Singapore
We are looking for postdocs / research fellows with expertise on cybersecurity in general and CPS security, applied cryptography, or applied ML in particular. The candidates should have track record of strong R&D capability, with publications at leading security conferences (http://jianying.space/conference-ranking.html).
We are also looking for research assistants / software engineers with strong programming skills and good knowledge of cybersecurity, computer networks and applied ML.
Only **short-listed** candidates will be contacted for interview. Successful candidates will be offered internationally competitive remuneration.
Interested candidates please send your CV to Prof. Jianying Zhou.
Closing date for applications:
Contact: Prof. Jianying Zhou (Email: jianying_zhou@sutd.edu.sg)
More information: http://jianying.space/
Input Output Global - remote work opportunity
IO Global is searching for a Cryptographic Engineer to join their Core Technology team. As Cryptographic Engineer you will have the exciting challenge of working on cutting-edge research and technology focusing on the market’s needs. You will be working with the Cardano-related projects, such as Cardano Core Cryptographic Primitives, Hydra, Mithril or Sidechains.
The Cryptography Engineering team is growing with the goal of bringing recent academic papers into production. In this team, you will work closely with researchers and engineers, being the bridge between both teams. As Cryptography Engineer you are responsible for writing high-quality code. To support you, our products have software architects, product managers, project managers, formal methods specialists, and QA test engineers, with whom you must communicate professionally, effectively, and efficiently.
Your mission
Working with teams across time zones
- Working independently on software development tasks
- Being proactive and requiring minimal supervision or mentoring to complete tasks
- Reviewing specifications produced by architects and formal methods specialists
- Contributing to the design of algorithms
- Troubleshooting, debugging, and upgrading software
- Writing documentation for the code
- Writing technical user manuals
- Understanding complex cryptographic concepts from academic papers
- Bridging ideas from academic papers to production ready systems.
Requirements
Your expertise
- Degree in computer science or mathematics is desirable, but not essential.
- Experience with systems programming (C/C++/Rust)
- Skilled in software development methods such as agile programming and test-driven development
- Experience in developing cryptography protocols would be a bonus, as would blockchain experience.
Location
IOG is a fully distributed organization and therefore this is a remote position. Due to team distribution we are ideally searching for someone in an European timezone.
Closing date for applications:
Contact: marios.nicolaides@iohk.io
More information: https://apply.workable.com/io-global/j/1B3EF63104/
Technology Innovation Institute (TII) - Abu Dhabi, UAE
Technology Innovation Institute (TII) is a publicly funded research institute, based in Abu Dhabi, United Arab Emirates. It is home to a diverse community of leading scientists, engineers, mathematicians, and researchers from across the globe, transforming problems and roadblocks into pioneering research and technology prototypes that help move society ahead.
Cryptography Research Center
In our connected digital world, secure and reliable cryptography is the foundation of digital information security and data integrity. We address the world’s most pressing cryptographic questions. Our work covers post-quantum cryptography, lightweight cryptography, cloud encryption schemes, secure protocols, quantum cryptographic technologies and cryptanalysis.
Position: Cryptography Hardware Engineer
Skills required for the job
Qualifications
Closing date for applications:
Contact: Mehdi Messaoudi - Talent Acquisition Manager
mehdi.messaoudi@tii.ae
16 September 2022
Benoît Libert, Ky Nguyen, Alain Passelègue
In this paper, we propose the first two instantiations of CALBO-TDFs based on standard assumptions. Our constructions are based on the LWE assumption with a sub-exponential approximation factor and on the DCR assumption, respectively, and circumvent the use of indistinguishability obfuscation by relying on lossy modes and trapdoor mechanisms enabled by these assumptions.
Federico Canale, Tim Güneysu, Gregor Leander, Jan Thoma, Yosuke Todo, Rei Ueno
A large variety of randomized cache architectures has been proposed. However, the actual randomization function received little attention and is often neglected in these proposals. Since the randomization operates directly on the critical path of the cache lookup, the function needs to have extremely low latency. At the same time, attackers must not be able to bypass the randomization which would nullify the security benefit of the randomized mapping. In this paper we propose \cipher (\underline{S}ecure \underline{CA}che \underline{R}andomization \underline{F}unction), the first dedicated cache randomization cipher which achieves low latency and is cryptographically secure in the cache attacker model. The design methodology for this dedicated cache cipher enters new territory in the field of block ciphers with a small 10-bit block length and heavy key-dependency in few rounds.
George Lu, Brent Waters
Our work explores the problem of sampling from discrete Gaussian (and related) distributions in a manner that they can be programmed into random oracles. We make the following contributions:
-We provide a definitional framework for our results. We say that a sampling algorithm $\mathsf{Sample}$ for a distribution is explainable if there exists an algorithm $\mathsf{Explain}$ where, for a $x$ in the domain, we have that $\mathsf{Explain}(x) \rightarrow r \in \{0,1\}^n$ such that $\mathsf{Sample}(r)=x$. Moreover, if $x$ is sampled from $\mathcal{D}$ the explained distribution is statistically close to choosing $r$ uniformly at random. We consider a variant of this definition that allows the statistical closeness to be a "precision parameter'' given to the $\mathsf{Explain}$ algorithm. We show that sampling algorithms which satisfy our `explainability' property can be programmed as a random oracle.
-We provide a simple algorithm for explaining \emph{any} sampling algorithm that works over distributions with polynomial sized ranges. This includes discrete Gaussians with small standard deviations.
-We show how to transform a (not necessarily explainable) sampling algorithm $\mathsf{Sample}$ for a distribution into a new $\mathsf{Sample}'$ that is explainable. The requirements for doing this is that (1) the probability density function is efficiently computable (2) it is possible to efficiently uniformly sample from all elements that have a probability density above a given threshold $p$, showing the equivalence of random oracles to these distributions and random oracles to uniform bitstrings. This includes a large class of distributions, including all discrete Gaussians.
-A potential drawback of the previous approach is that the transformation requires an additional computation of the density function. We provide a more customized approach that shows the Miccancio-Walter discrete Gaussian sampler is explainable as is. This suggests that other discrete Gaussian samplers in a similar vein might also be explainable as is.
Hao Guo, Jintai Ding
Protocol Labs, Remote
Closing date for applications:
Contact: Luke Sandquist
More information: https://boards.greenhouse.io/protocollabs/jobs/4616824004
UNSW, Sydney, Australia
- Post Quantum Cryptography for Blockchains
- Towards a Quantum-Safe Internet
Prospective students are expected to have strong mathematical inclination and strong background in data structures, discrete mathematics and algorithms. Candidates with knowledge of cryptography (such as completion of undergraduate/graduate course or research project) will be preferred.
Open to students who have completed a bachelor’s degree or a master’s degree in Computer Science, Mathematics or a related discipline. Candidates in their final year of study are welcome to apply.
SQA Deadline: September 26, 2022.
UNSW Deadline: September 30, 2022.
Closing date for applications:
Contact: Please contact Dr. Sushmita Ruj (Email: Sushmita.ruj@unsw.edu.au) with your CV and transcripts if you are interested.
More information: https://www.sydneyquantum.org/program/sqa-phd-scholarships/
Sorbonne Université, Paris, France
Closing date for applications:
Contact: Eleni Diamanti, Laboratoire d’Informatique de Sorbonne Université (LIP6)
Inria of the University of Rennes
Closing date for applications:
Contact: Davide Frey
More information: https://recrutement.inria.fr/public/classic/fr/offres/2022-05366
QuSoft / University of Amsterdam
The Theory of Computer Science (TCS) group at the Informatics Institute (IvI) of the University of Amsterdam (UvA) is looking for an excellent candidate for a fully funded PhD position as part of QSI (Quantum-Safe Internet), a Marie Curie Innovative Training Network (MSCA-ITN). The QSI network involves top-ranking partner universities from France, Italy, Germany, the Netherlands, Denmark, Spain, the UK, and Switzerland, as well as industrial partners.
You will conduct research at the intersection of quantum and post-quantum cryptography and publish/ present the results at top venues for research in crypto/ IT Security. You will be supervised by Prof. Christian Schaffner and Dr. Florian Speelman.
We are looking for a candidate with:- a MSc in computer science, mathematics, or a related field;
- strong academic performance in university-level courses related to cryptography, IT security, theoretical CS, or mathematics;
- professional command of English and good presentation skills;
- compliance with the MSCA-ITN mobility rule: you must not have resided or carried out your main activity (work, studies, etc.) in the Netherlands for more than 12 months in the 36 months immediately before your recruitment date.
- Full-time employment for the duration of the PhD
- A well-rounded training offered by the QSI network, covering a range of topics related to secure communications in the quantum era, as well as complementary training intended to enhance your personal development.
- Generous travel budget that allows for, e.g., exposure to different sectors via planned placements and attendance to summer schools.
Closing date for applications:
Contact: Prof. Christian Schaffner
More information: https://vacatures.uva.nl/UvA/job/PhD-Quantum-Cryptography/754463502/
George Mason University
The George Mason University and Commonwealth Cyber Initiative (CCI), within the College of Engineering and Computing (CEC), invites applications for an Associate/Full Professor of Cybersecurity and Commonwealth Cyber Initiative Fellow position. GMU has a strong institutional commitment to the achievement of excellence and diversity among its faculty and staff, and strongly encourages candidates to apply who will enrich Mason’s academic and culturally inclusive environment.
About the Position:
The incumbent will conduct research at GMU and as part of the Northern Virginia Node of the Commonwealth Cyber Initiative, and in partnership with researchers from the Coastal Node of the Commonwealth Cyber Initiative and Old Dominion University. Successful candidates will have access to the faculty and facilities of both GMU and Old Dominion University to enable their success.
Responsibilities:
Serve as the director of the interdisciplinary research effort between GMU, Old Dominion University and the Northern Virginia and Coastal Nodes of the CCI;
Leverage university-level strategic priorities in cybersecurity research to lead transformative growth and impact the research portfolio, and to further encourage and foster new and existing collaborations with academic, industrial, and governmental institutions in Northern Virginia, Coastal Virginia and the greater Washington, D.C., area;
Accelerate the growth of high-quality academic programs, facilitate interdisciplinary research initiatives, and broaden the scope and focus areas of research in Mason with significant potential for commercialization.
Required Qualifications:
Doctorate in CS, ECE, IT, or a related field;
Eligible for a tenured appointment as associate or full professor;
Outstanding cybersecurity research and publication record;
Commitment to excellence in both graduate and undergraduate education
significant leadership experience
US citizen
Closing date for applications:
Contact: More information: https://jobs.chronicle.com/job/37290398/associatefull-professor-of-cybersecurity-and-commonwealth-cyber-initiative-fellow?