IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
15 March 2024
Hermann Seuschek, Johann Heyszl, Fabrizio De Santis
Wenhao Zhang, Xiaojie Guo, Kang Yang, Ruiyu Zhu, Yu Yu, Xiao Wang
1) We propose an actively secure protocol for distributed point function (DPF), with one-bit leakage, that is essentially as efficient as the state-of-the-art semi-honest protocol. Compared with previous work, our protocol takes about $50 \times$ less communication for a domain with $2^{20}$ entries, and no longer requires actively secure generic 2PC.
2) We extend the dual-execution protocol to allow reactive computation, and then build a RAM-based 2PC protocol with active security on top of our new building blocks. The protocol follows the paradigm of Doerner and shelat (CCS 2017). We are able to prove that the protocol has end-to-end one-bit leakage.
3) Our implementation shows that our protocol is almost as efficient as the state-of-the-art semi-honest RAM-based 2PC protocol, and is at least two orders of magnitude faster than prior actively secure RAM-based 2PC without leakage, providing a realistic trade-off in practice.
Marshall Ball, Yanyi Liu, Noam Mazor, Rafael Pass
We demonstrate that when $t$ is some polynomial, then not only does this hardness assumption imply the existence of KA, but it is also necessary for the existence of secure KA. As such, it yields the first natural hardness assumption characterizing the existence of key-agreement protocols.
We additionally show that when the threshold $s$ is bigger (e.g., $s = 55log n$), then the (worst-case) hardness of this problem instead characterizes the existence of one-way functions (OWFs). As such, our work also clarifies exactly what it would take to base KA on the existence of OWFs, and demonstrates that this question boils down to demonstrating a worst-case reduction between two closely related promise problems.
Flavio Bergamaschi, Anamaria Costache, Dana Dachman-Soled, Hunter Kippen, Lucas LaBuff, Rui Tang
In this work, we ask whether there is an intermediate noise-flooding level, which may not be provably secure, but allows to maintain the performance of the scheme, while resisting known attacks. We analyze the security with respect to different adversarial models and various types of attacks.
We investigate the effectiveness of lattice reduction attacks, guessing attacks and hybrid attacks with noise-flooding with variance $\rho^2_{\mathsf{circ}}$, the variance of the noise already present in the ciphertext as estimated by an average-case analysis, $100\cdot \rho^2_{\mathsf{circ}}$, and $t\cdot \rho^2_{\mathsf{circ}}$, where $t$ is the number of decryption queries. For noise levels of $\rho^2_{\mathsf{circ}}$ and $100\cdot \rho^2_{\mathsf{circ}}$, we find that a full guessing attack is feasible for all parameter sets and circuit types. We find that a lattice reduction attack is the most effective attack for noise-flooding level $t\cdot \rho^2_{\mathsf{circ}}$, but it only induces at most a several bit reduction in the security level.
Due to the large dimension and modulus in typical FHE parameter sets, previous techniques even for estimating the concrete security of these attacks -- such as those in (Dachman-Soled, Ducas, Gong, Rossi, Crypto '20) -- become computationally infeasible, since they involve high dimensional and high precision matrix multiplication and inversion. We therefore develop new techniques that allow us to perform fast security estimation, even for FHE-size parameter sets.
Konstantina Miteloudi, Asmita Adhikary, Niels van Drueten, Lejla Batina, Ileana Buhan
Deepak Kumar Dalai, Krishna Mallick
Xiangyu Hui, Sid Chi-Kin Chau
13 March 2024
University of Rennes, France
Closing date for applications:
Contact: Sylvain Duquesne
University of Luxembourg
The candidate will be based at the University of Luxembourg but also profit from regular visits at and joint research projects with the KASTEL Security Research Labs.
The candidate’s research will be dealing with privacy-preserving cryptographic building blocks and protocols for important application scenarios and result in both theoretical contributions (protocol designs, security models and proofs, etc.) and their efficient implementation. Privacy-preserving payments and data analytics, misuse-resistant lawful interception, and anonymous communication are research topics of particular interest to us.
If you are interested in joining our group, please send an email including your CV, transcripts, and two references to andy.rupp@uni.lu. As the position should be filled as soon as possible, your application will be considered promptly.
Closing date for applications:
Contact: Andy Rupp (andy.rupp@uni.lu)
More information: https://www.uni.lu/fstm-en/research-groups/cryptographic-protocols-crypo/
11 March 2024
Birmingham, United Kingdom, 5 August - 9 August 2024
Marhaba Palace, Tunisie, 22 October - 26 October 2024
Submission deadline: 5 May 2024
Notification: 12 July 2024
Rockville, USA, 20 June - 21 June 2024
Submission deadline: 1 May 2024
Notification: 17 May 2024
Lund University
The position is funded within the framework of a special initiative on cybersecurity from the Wallenberg AI, Autonomous Systems and Software Program. This means that, in addition to funding for the Assistant Lecturer position, full funding is provided for doctoral positions associated with the new position. The new Assistant Lecturer is expected to actively participate in the supervision of these doctoral students and, once docent competence is achieved, take on the main supervisory role. Additionally, funding is provided for two postdoctoral positions for two years each within the employment. The new Assistant Lecturer is expected to be responsible for developing profiles and recruiting for these two positions.
The subject of the position encompasses methods and principles for protecting data in safety-critical applications, as well as protection against overload attacks and the maintenance of personal privacy. There are significant challenges in researching how machine learning can be used to attack traditional computer systems, but also to create new principles for protecting systems, making them more robust, and, not least, automating security architectures and protection systems.
Work duties include:
- Research within the subject area,
- Teaching in the first, second and third cycles of studies,
- Supervision of degree projects and doctoral students,
- Actively seeking external research funding,
- Collaboration with industry and wider society.
- Recruitment of researchers and building up a research group,
- Administration related to the work duties listed above.
Closing date for applications:
Contact: Christian Gehrmann, christian.gehrmann@eit.lth.se
More information: https://lu.varbi.com/en/what:job/jobID:688687/
Quantstamp
Quantstamp is looking for an applied cryptographer. Quantstamp often deals with a wide range of cryptographic problems, including reviewing implementations and tackling new theoretical problems using cryptography. For example, Quantstamp regularly receives requests to review code bases which either invoke or implement (custom) cryptography, as part of an audit.
Required
Closing date for applications:
Contact: candidate-upload-to-job-N7wnRj36Krf2zX@inbox.ashbyhq.com
More information: https://quantstamp.com/careers
Noam Mazor, Rafael Pass
In more detail: - Assuming the existence of indistinguishability obfuscation, and subexponentially-secure one-way functions, an appropriate Gap version of MCSP is not NP-complete under randomized Levin-reductions. - Assuming the existence of subexponentially-secure indistinguishability obfuscation, subexponentially-secure one-way functions and injective PRGs, an appropriate Gap version of MKTP is not NP-complete under randomized Levin-reductions.