IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
12 April 2022
Steven D. Galbraith, Yi-Fu Lai
Tingting Guo, Peng Wang, Lei Hu, Dingfeng Ye
Paola de Perthuis, David Pointcheval
We study two interesting particular cases: - 2-party Inner-Product Functional Encryption, with $\mathbf{\alpha}= (1,\ldots,1)$. There is a unique functional decryption key, which enables the computation of $\mathbf{x}\cdot \mathbf{y}^\top$ by a third party, where $\mathbf{x}$ and $\mathbf{y}$ are provided by two independent clients; - Inner-Product Functional Encryption with a Selector, with $\mathbf{x}= \mathbf{x}_0 \| \mathbf{x}_1$ and $\mathbf{y}= \bar{b}^n \| b^n \in \{ 1^n \| 0^n, 0^n \| 1^n \}$, for some bit $b$, on the public coefficients $\mathbf{\alpha} = \mathbf{\alpha}_0 \| \mathbf{\alpha}_1$, in the functional decryption key, so that one gets $\mathbf{x}_b \cdot \mathbf{\alpha}_b^\top$, where $\mathbf{x}$ and $b$ are provided by two independent clients.
This result is based on the fundamental Product-Preserving Lemma, which is of independent interest. It exploits Dual Pairing Vector Spaces (DPVS), with security proofs under the \mathsf{SXDH} assumption. We provide two practical applications to medical diagnosis for the latter IPFE with Selector, and to money-laundering detection for the former 2-party IPFE, both with strong privacy properties, with adaptative security and the use of labels granting a Multi-Client Functional Encryption (MCFE) security for the scheme, thus enabling its use in practical situations.
Jordi Ribes-González, Oriol Farràs, Carles Hernández, Vatistas Kostalabros, Miquel Moretó
In this work, we tackle the problem of formally defining and analyzing the security properties of RPCs. We first give security definitions against access-based cache side-channel attacks that capture security against known attacks such as Prime+Probe and Evict+Probe. Then, using these definitions, we obtain results that allow to guarantee security by adequately choosing the rekeying period, the key generation algorithm and the cache randomizer, thus providing security proofs for RPCs under certain assumptions.
Hanno Becker, Vincent Hwang, Matthias J. Kannwischer, Lorenz Panny, Bo-Yin Yang
11 April 2022
University of Plymouth in Applied Cryptography
Closing date for applications:
Contact: Dr. Hai-Van Dang
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Submission deadline: 2 May 2022
Notification: 1 December 2022
University of Luxembourg
We offer a competitive salary (about 37,000 euro/year gross for Ph.D, and 64,000 euro/year gros for post-doc). The duration of the position is 3 years (+ 1 year extension) for Ph.D., and 2.5 years for post-doc.
Profile:
- For Ph.D. position: MSc degree or equivalent in Computer Science or in Mathematics.
- For post-doc position: a PhD in cryptography, with publications in competitive cryptographic conferences
Closing date for applications:
Contact: Prof. Jean-Sebastien Coron - jean-sebastien.coron at uni dot lu
More information: http://www.crypto-uni.lu/vacancies.html
New Jersey Institute of Technology (NJIT), USA
Details: NJIT is a Rank 1 Research University, situated in New York Metropolitan area, and is about 7 miles away from the beautiful New York City. New York Metropolitan area is a key part of the US and is the hub of several major tech and research companies. The qualified candidates will have opportunities for research internships and joint projects with lead-industrial companies. The position is looking for highly motivated graduate students to explore, design, and implement algorithms for databases, secure computing, IoT, and blockchain.
Topics are as follows:
- Design and implementation of an end-to-end-secure database system using MPC or secret-sharing
- Algorithm development for side-channel attacks on MPC
Requirements: 1. Adequate knowledge of cryptographic techniques/algorithms, programming, and relational database systems 2. Knowledge of Java, SQL, and C/C++ 3. Familiarity with development tools for managing and building software projects, version control systems (Git), and testing tools (JUnit) 4. You must be an Undergraduate/Master student in computer science or a related field
Additional Information:
1. Starting date: As soon as possible 2. Please send your CV and other information (e.g., github account, sample projects, etc.) to: Shantanu Sharma (shantanu.sharma[AT]njit[DOT]edu) 3. Please write a few sentences in the email to introduce yourself and your interest in the position
Thank you and I look forward to hearing from you!
Closing date for applications:
Contact: Shantanu Sharma (shantanu.sharma[AT]njit[DOT]edu)
More information: https://web.njit.edu/~ss797/students.html
07 April 2022
Subspace Labs
Subspace Network is building a radically decentralized, next-generation blockchain which allows developers to easily run Web3 apps at Internet scale. Subspace is based on original research funded by the US National Science Foundation and plans to launch its Network later this year. Subspace Labs is an early-stage, venture-backed startup with a remote-first, globally distributed team.
We are seeking a Protocol Researcher to join our rapidly growing team of Blockchain and Cryptocurrency enthusiasts and engineers. As a Protocol Research you will be responsible for formally analyzing the security claims of the Subspace Network. Your goal is to formally prove these claims or suggest improvement to the protocol as needed to support them. This shall result in a series of formal specifications and peer-reviewed papers.
As a Protocol Researcher you will: Analyze and validate our solutions to some of the hardest problems in the blockchain space, as they relate to Nakamoto consensus, decentralized storage, decoupled execution, crypto-economic incentives, and the scaling trilemma; research and propose solutions to open problems or unsubstantiated claims; develop a series of formal specifications that codify and clarify our solutions; collaborate directly with our protocol engineering team to ensure that specifications are clearly understood and implemented correctly; iterate findings into research papers suitable for peer-reviewed publication; work directly with our university partners, academic advisors, and third party engineering security partners on formal security analyses and audits; present research finding at industry events and university conferences; distribute and discuss results in our open-source online research forum.
Position Requirements: A PhD in Computer Science, Cryptography or a related field, and a strong record of peer-reviewed publications in cryptography, distributed systems, or peer-to-peer network, as they relate to blockchain protocols.
Closing date for applications:
Contact: Sky McWilliams, Director of People
More information: https://jobs.lever.co/subspacelabs/95bd61e2-8aae-4109-89df-67b7350263c8?lever-origin=applied&lever-source%5B%5D=IACR
Input Output Global - remote work opportunity
As a Principal Architect in Applied Cryptography at IOG, you must be an engineer, an architect, an applied cryptographer, and a leader - it’s a multifaceted role. You have the exciting challenge of working with bleeding-edge research and technology, always with a focus on the market's needs. You will be a leader of an exceptional team, working on everything from Post-Quantum prototypes to hand-optimization of existing primitives to completely new products. To support you on this challenge, we have software architects, product managers, project managers, formal methods specialists, and QA test engineers, with whom you must have high bandwidth communications.
Your mission
- Champion the applied cryptography team
- Captain end-to-end development and delivery of new products
- Spearhead prototyping of cryptographic products
- Translate research into rigorous engineering specifications and implementations
- Meticulously review cryptographic protocols and proposed primitives
- Contribute to industry standards and operational best practices
- Identify where the business needs to be next and get it there.
Closing date for applications:
Contact:
https://apply.workable.com/io-global/j/8D6CAEE7DD/
marios.nicolaides@iohk.io
More information: https://apply.workable.com/io-global/j/8D6CAEE7DD/
Subspace Labs
Subspace Network is building a radically decentralized, next-generation blockchain which allows developers to easily run Web3 apps at Internet scale. Subspace is based on original research funded by the US National Science Foundation and planning to launch its Network later this year. Subspace Labs is an early-stage, venture-backed startup with a remote-first, globally distributed team.
We are seeking a Director of Research to join our rapidly growing team of Blockchain and Cryptocurrency enthusiasts and engineers. As our Director of Research you will primarily be responsible for building and leading a team of protocol researchers. The research team will be responsible for analyzing the security of the Subspace Network, formalizing our specifications, and publishing relevant research results in the peer-reviewed setting.
Responsibilities: Collaborate directly with the CEO & CTO to translate our existing white paper, documentation, and protocol roadmap into a set of formal specifications; identify the key security challenges and develop a long-term research and publication roadmap which addresses them; ensure research findings are continuously fed back into the protocol design and implementation; recruit hire and lead our international protocol research team, consisting of research scientists, post-doctoral researchers, and graduate research interns; work directly with our university partners, academic advisors, and third party engineering security partners to facilitate formal security analyses and audits; design and administer an open-source online research forum and work to engage the global research community in the security analysis of our protocol.
Requirements: A PhD in Computer Science, Cryptography or a related field; strong record of peer-reviewed publications in cryptography, distributed systems, or peer-to-peer network, as they relate to blockchain technologies.
Closing date for applications:
Contact: CEO & Co-Founder, Jeremiah Wagstaff
More information: https://subspace.network/
Sunscreen; San Francisco, USA or remote
What you'll accomplish your 1st year here...
You...
We offer...
Closing date for applications:
Contact: Ravital Solomon (ravital@sunscreen.tech)
More information: https://www.notion.so/Jobs-at-Sunscreen-6966db120ec3425ead92f64b40d4cb17?p=6516320b644547c9b0ef4940684e2dc2
University of Neuchatel
Jointly at the Institute of Computer Science and the Institute of Mathematics
Full time 100%
Requirements:
• PhD in Computer Science or Mathematics (obtained up to 10 years ago)
• Good scientific knowledge in Computer Science and Mathematics
• Sustained teaching experience
• Strong interest in interdisciplinary approaches
Activities:
• Teaching in Computer Science and Mathematics: up to 4 hours per week at Bachelor and Master level in French and in English
• Student supervision
• Research development
• Participation in administrative tasks at the institutes
Start date: 01.08.2022 or to be agreed
Position duration: 4 years, renewable 2 years / legal treatment and obligations
The application of each candidate must include a letter of motivation, a curriculum vitae and a copy of the titles earned. A complete application file shall be sent in one PDF file to the address secretariat.iiun@unine.ch. The applications will be evaluated starting from May 1st 2022 until the position is filled.
The salary is defined according to the scale of the University of Neuchâtel, see http://www.unine.ch/srh/maitres-assistant-e-s-mer
Further information can be obtained by Prof. Pascal Felber pascal.felber@unine.ch and Prof. Elisa Gorla elisa.gorla@unine.ch, as well as on the page www.unine.ch/sciences
L'Université de Neuchâtel s'engage activement à la mise en oeuvre de sa responsabilité et offre des conditions de travail non discriminatoires, les candidatures féminines sont spécifiquement encouragées.
Closing date for applications:
Contact: Prof. Pascal Felber pascal.felber@unine.ch and Prof. Elisa Gorla elisa.gorla@unine.ch
More information: http://www.unine.ch/sciences
06 April 2022
Benjamin Wesolowski
Aparna Gupte, Neekon Vafa, Vinod Vaikuntanathan
As a concrete application, we show an improved hardness result for density estimation for mixtures of Gaussians. In this computational problem, given sample access to a mixture of Gaussians, the goal is to output a function that estimates the density function of the mixture. Under the (plausible and widely believed) exponential hardness of the classical LWE problem, we show that Gaussian mixture density estimation in $\mathbb{R}^n$ with roughly $\log n$ Gaussian components given $\mathsf{poly}(n)$ samples requires time quasi-polynomial in $n$. Under the (conservative) polynomial hardness of LWE, we show hardness of density estimation for $n^{\epsilon}$ Gaussians for any constant $\epsilon > 0$, which improves on Bruna, Regev, Song and Tang (STOC 2021), who show hardness for at least $\sqrt{n}$ Gaussians under polynomial (quantum) hardness assumptions. Our key technical tool is a reduction from classical LWE to LWE with $k$-sparse secrets where the multiplicative increase in the noise is only $O(\sqrt{k})$, independent of the ambient dimension $n$.
Marc Rivinius, Pascal Reisert, Daniel Rausch, Ralf Küsters
Frédéric Dupuis, Philippe Lamontagne, Louis Salvail
We show that WOTRO with $n - m \in \omega(\lg n)$ is black-box impossible in the CRQS model, meaning that no protocol can have its security black-box reduced to a cryptographic game. We define a (inefficient) quantum adversary against any WOTRO protocol that can be efficiently simulated in polynomial time, ruling out any reduction to a secure game that only makes black-box queries to the adversary. On the other hand, we introduce a non-game quantum assumption for hash functions that implies WOTRO in the CRQS model (where the CRQS consists only of EPR pairs). We first build a statistically secure WOTRO protocol where $m = n$, then hash the output.
The impossibility of WOTRO has the following consequences. First, we show the black-box impossibility of a quantum Fiat-Shamir transform, extending the impossibility result of Bitansky et al. (TCC '13) to the CRQS model. Second, we show a black-box impossibility result for a strenghtened version of quantum lightning (Zhandry, Eurocrypt '19) where quantum bolts have an additional parameter that cannot be changed without generating new bolts.
Takashi Yamakawa, Mark Zhandry
- There are NP search problems solvable by BQP machines but not BPP machines.
- There exist functions that are one-way, and even collision resistant, against classical adversaries but are easily inverted quantumly. Similar separations hold for digital signatures and CPA-secure public key encryption (the latter requiring the assumption of a classically CPA-secure encryption scheme). Interestingly, the separation does not necessarily extend to the case of other cryptographic objects such as PRGs.
- There are unconditional publicly verifiable proofs of quantumness with the minimal rounds of interaction: for uniform adversaries, the proofs are non-interactive, whereas for non-uniform adversaries the proofs are two message public coin.
- Our results do not appear to contradict the Aaronson-Ambanis conjecture. Assuming this conjecture, there exist publicly verifiable certifiable randomness, again with the minimal rounds of interaction.
By replacing the random oracle with a concrete cryptographic hash function such as SHA2, we obtain plausible Minicrypt instantiations of the above results. Previous analogous results all required substantial structure, either in terms of highly structured oracles and/or algebraic assumptions in Cryptomania and beyond.