IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
02 May 2022
Mo Zhang, Eduard Marin, David Oswald, Vassilis Kostakos, Mark Ryan, Benjamin Tag, Kleomenis Katevas
Liam Eagen
Using the permutation argument, as well as a new variant of the weighted inner product argument for weighted norms, Bulletproofs++ range proofs can support larger bases and achieve much smaller witness sizes. For a 64 bit range, representing the value as 16 hexadecimal digits reduces the length of the witness per commitment by a factor of approximately 6, asymptotically approaching 8 as the number of values increases. The proof size for a single value using Curve25519 is 416 bytes, which is 160 bytes smaller than Bulletproofs+. This technique has a small asymptotic affect on the witness size, going from O(n) to O(n/log n) where n is the number of bits required to encode all the values to be proven.
For confidential transactions, the ``elements" of the multiset are the types of currency and the multiplicities are the amounts for each input. Since the argument is linear in the elements of the set, multiple provers can show that all the inputs and outputs for a transaction satisfy typed conservation of money without breaking their mutual privacy. This confidential transaction protocol has essentially the same structure as the generic base range proof and can be added to a range proof at minimal additional cost to make a confidential transaction protocol.
29 April 2022
The deadline for nominations is May 2nd: https://ches.iacr.org/2022/testoftime.php
Brandenburg University of Technology
- 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
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
Applications containing the following documents:
- A detailed Curriculum Vitae
- Transcript of records from your Master studies
- An electronic version of your Master thesis should be sent in a single PDF file as soon as possible, but not later than 15.05.2022 at itsec-jobs.informatik@lists.b-tu.de
Closing date for applications:
Contact: Prof. Andriy Panchenko
More information: https://www.b-tu.de/en/fg-it-sicherheit
University of Sheffield, Department of Computer Science; United Kingdom
This is an exciting opportunity for a Lecturer/Senior Lecturer in Cybersecurity at the University of Sheffield. You will join the Security of Advanced Systems Research Group, led by Professor John Clark. Sheffield’s strength in engineering brings many opportunities for collaborative research in cybersecurity, in areas such as smart buildings, robotics and advanced manufacturing.
We are seeking a candidate with an outstanding record of scholarship in cybersecurity. Suitable areas of expertise include (but are not limited to): formalisation and proof of system security properties, development of security protocols, cryptographic fundamentals, authentication mechanisms (e.g., protocols and biometrics), security of modern systems architectures and supporting technologies (IoT, cloud, software defined networks, low latency networks, 5G, low resource systems), and the use of machine learning to secure or stress test systems. Specific application areas include, but are not limited to, energy networks, active buildings, robotics and advanced manufacturing.
You will hold a PhD in computer science or a related area, and you will be able to conduct research to the highest standards. You will secure research funding, publish in high impact journals, supervise research students and manage research projects. As a teacher, you will play a key role in maintaining our reputation for high-quality teaching by designing, delivering and assessing undergraduate and postgraduate-level courses in cybersecurity and other core topics in computer science. We seek candidates who will be able to make a distinctive individual contribution to our cybersecurity research portfolio, collaborating with the group and more widely.
We build teams of people from different heritages and lifestyles whose talent and contributions complement, and believe diversity in all its forms delivers greater impact through research, teaching and student experience. The appointment will be supported with a generous start-up package including funds for equipment/travel and a PhD studentship (covering UK tuition fee and stipend for 3.5 years).
Deadline: 11th May, 2022.Closing date for applications:
Contact:
For information about the role, contact John Clark: john.clark@sheffield.ac.uk.
For information about the application process, contact Joanna Lawrence: j.l.lawrence@sheffield.ac.uk.
More information: https://www.jobs.ac.uk/job/COY785/lecturer-senior-lecturer-in-cybersecurity
Lucca, Italia, 17 June 2022
Submission deadline: 11 May 2022
Notification: 20 May 2022
University of Passau, Germany
Closing date for applications:
Contact: Ektor Arzoglou (ektor.arzoglou@uni-passau.de)
More information: https://www.fim.uni-passau.de/en/computer-engineering
28 April 2022
Corentin Jeudy, Adeline Roux-Langlois, Olivier Sanders
Lorenzo Grassi, Bart Mennink
In this paper, we reconsider truncation of a permutation, and prove that the construction is indifferentiable from a random oracle, even if this fixed initial value is replaced by a randomized value. This randomized value may be the same for different evaluations of the construction, or freshly generated, up to the discretion of the adversary. The security level is the same as that of truncation with fixed initial value, up to collisions in the randomized value.
We show that our construction has immediate implications in the context of parallel variable-length digest generation. In detail, we describe Cascade-MGF, that operates on top of any cryptographic hash function and uses the hash function output as randomized initial value in truncation. We demonstrate that Cascade-MGF compares favorably over earlier parallel variable-length digest generation constructions, namely Counter-MGF and Chained-MGF, in almost all settings.
David Knichel, Amir Moradi
Jens Groth, Victor Shoup
This service is being implemented and integrated into the architecture of the Internet Computer, enabling smart contracts running on the Internet Computer to securely hold and spend Bitcoin and other cryptocurrencies.
Rishub Nagpal, Barbara Gigerl, Robert Primas, Stefan Mangard
Ziaur Rahman, Xun Yi, Sk. Tanzir Mehedi, Rafiqul Islam, Andrei Kelarev
Peter Beerel, Marios Georgiou, Ben Hamlin, Alex J. Malozemoff, Pierluigi Nuzzo
Vlastimil Klima
Dedy Septono Catur Putranto, Rini Wisnu Wardhani, Harashta Tatimma Larasati, Howon Kim
Reo Eriguchi, Kaoru Kurosawa, Koji Nuida
Varun Madathil, Sri AravindaKrishnan Thyagarajan, Dimitrios Vasilopoulos, Lloyd Fournier, Giulio Malavolta, Pedro Moreno-Sanchez
All known solutions to implement oracle-based contracts rely either on Turing-complete smart contracts or on trusted hardware. In particular, no solution comes with provable cryptographic guarantees that are compatible with many popular cryptocurrencies, such as Bitcoin. In this work, we lay the foundations of oracle contracts for cryptocurrencies. We present game-based definitions that model the security properties of oracle contracts and we propose the first construction with provable security guarantees. As a contribution of independent interest and as our main technical building block, we show an efficient construction of \emph{witness encryption} for the following class of languages: $$ \{ (\vk, m) \in \mathcal{L} : \exists~\sigma \text{ s.t. }\mathsf{Verify}(\vk, \sigma, m) = 1\} $$ where $\sigma$ is a BLS digital signature on $m$. We show how this can be extended to the threshold settings and how to efficiently prove that the encrypted message has a certain structure. The former allows distribution of trust among several ``Oracles'' and to guarantee the latter, we develop a new batching technique for cut-and-choose, inspired by the work of Lindell-Riva on garbled circuits.
Petr Sedláček
Carmit Hazay, Muthuramakrishnan Venkitasubramaniam, Mor Weiss
Our main technical contribution is designing the first secret-sharing scheme that is equivocal, resists adaptive probing of a constant fraction of bits from each share, while incurring only a constant blowup in share size. Equivocation is a strong leakage-resilience guarantee, recently introduced by Hazay et al. (ITC`21). Our construction is obtained via a general compiler which we introduce, that transforms any secret-sharing scheme into an equivocal scheme against adaptive leakage. An attractive feature of our compiler is that it respects additive reconstruction, namely, if the original scheme has additive reconstruction, then the transformed scheme has linear reconstruction.
We extend our compiler to a general paradigm for protecting distributed primitives against leakage, and show its applicability to various primitives, including secret sharing, verifiable secret sharing, function secret sharing, distributed encryption and signatures, and distributed zero-knowledge proofs. For each of these primitives, our paradigm transforms any construction of the primitive into a scheme that resists adaptive party corruptions, as well as adaptive probing leakage of a constant fraction of bits in each share when the share is stored in memory (but not when it is used in computations). Moreover, the transformation incurs only a constant blowup in the share size, and respects additive reconstruction - an important feature for several of these primitives, such as function secret sharing and distributed encryption.