IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
12 December 2023
François-Xavier Wicht, Zhipeng Wang, Duc V. Le, Christian Cachin
Cong Ling, Andrew Mendelsohn
11 December 2023
Technical University of Denmark, Dept. of Applied Mathematics and Computer Science, Copenagen Area
The goal of the project is to explore different routes towards providing a fully quantum-secure replacement for X3DH, the key exchange protocol used by Signal, WhatsApp and the likes. It is an excellent opportunity to be involved in advanced research on cryptographic systems secure against quantum computing.
For more information click the title of this job listing. If you are interested feel free to reach out to Christian Majenz (chmaj@dtu.dk).
Closing date for applications:
Contact: Christian Majenz, Associate Professor at DTU Compute, Cyber Security Engineering Section
More information: https://efzu.fa.em2.oraclecloud.com/hcmUI/CandidateExperience/en/sites/CX_1/job/2851/?utm_medium=jobshare
University of Kassel, Germany
The Information Security group is looking for a strong candidate to fill an open PhD position. The PhD will be supervised by Jiaxin Pan and will work on provable security, for instance, key exchange protocols and digital signature schemes. We will also work on the post-quantum security of them.
We hope that the PhD can publish at major venues, such as Crypto, Eurocrypt, Asiacrypt, PKC, etc., under the supervision. In the past, this has been successfully realized.
The position is paid according to EG13 TV-H (full-time). It is initially limited for 3 years with the possibility of extension for a further 2 years. The position comes with teaching load of 4 hours per week during the semester teaching period. This is usually manageable and can be done in the forms of tutorials, labs, seminars, or thesis co-supervision.
We encourage strong candidates with a Master degree and those who are close to finish to apply. Knowledge in post-quantum cryptography, digital signatures, or key exchange is highly desirable.
More information can be found in:
- https://stellen.uni-kassel.de/jobposting/9023eb9d3fd3366877c376079417eb1d088ded3c0 (English), or
- https://stellen.uni-kassel.de/jobposting/0870f187f0392f19987735519cbe2b5778a3eb910 (German)
Closing date for applications:
Contact: Jiaxin Pan: https://sites.google.com/view/jiaxinpan
More information: https://stellen.uni-kassel.de/jobposting/9023eb9d3fd3366877c376079417eb1d088ded3c0
University of Birmingham, UK
Closing date for applications:
Contact: Rishiraj Bhattacharyya (r.bhattacharyya@bham.ac.uk)
More information: https://edzz.fa.em3.oraclecloud.com/hcmUI/CandidateExperience/en/sites/CX_6001/job/3750/
Limitless Labs, Ukraine or Remote
This role is dedicated to applied research. In our initial phases, we are committed to understanding and leveraging the state-of-the-art, while in future phases, we will advance it. Primarily, the researcher will contribute to the design of new architectural solutions.
Responsibilities
- Design, specify and verify distributed systems by leveraging formal and experimental techniques.
- Build proof of concepts and prepare executable specifications for the development team.
- Regularly going through papers, bringing new ideas and staying up-to-date.
- Conducting theoretical and practical analysis of the performance of distributed systems.
- Collaborating with both internal and external contributors.
Closing date for applications:
Contact: Ira | Head of People @ Limitless Labs
More information: https://apply.workable.com/limitless-labs-network/j/EF6246F619/
Mingxun Zhou, Elaine Shi, Giulia Fanti
To address this challenge, we propose an efficient protocol called Shuffle-ZKP, which enables users within an unlinkable messaging system to collectively prove their compliance. Our protocol leverages a distributed and private set equality check protocol along with generic Non-Interactive Zero-Knowledge (NIZK) proof systems. We also provide an additional attributing protocol to identify misbehaving users. We theoretically analyze the protocol's correctness and privacy properties; we then implement and test it across multiple use cases. Our empirical results show that in use cases involving thousands of users, each user is able to generate a compliance proof within 0.2-10.6 seconds, depending on the use case, while the additional communication overhead remains under 3KB. Furthermore, the protocol is computationally efficient on the server side; the verification algorithm requires a few seconds to handle thousands of users in all of our use cases.
Tom Azoulay, Uri Carl, Ori Rottenstreich
Ori Mazor, Ori Rottenstreich
Sajin Sasy, Adithya Vadapalli, Ian Goldberg
Colin Putman, Keith M. Martin
Clément Hoffmann, Pierrick Méaux, François-Xavier Standaert
Yilei Chen, Jiatu Li
In this paper, we demonstrate, under plausible cryptographic assumptions, that both the range avoidance problem and the remote point problem cannot be efficiently solved by nondeterministic search algorithms, even when the input circuits are as simple as constant-depth circuits. This extends a hardness result established by Ilango, Li, and Williams (STOC '23) against deterministic algorithms employing witness encryption for $\textsf{NP}$, where the inputs to $\textsf{Avoid}$ are general Boolean circuits.
Our primary technical contribution is a novel construction of witness encryption inspired by public-key encryption for certain promise language in $\textsf{NP}$ that is unlikely to be $\textsf{NP}$-complete. We introduce a generic approach to transform a public-key encryption scheme with particular properties into a witness encryption scheme for a promise language related to the initial public-key encryption scheme. Based on this translation and variants of standard lattice-based or coding-based PKE schemes, we obtain, under plausible assumption, a provably secure witness encryption scheme for some promise language in $\textsf{NP}\setminus \textsf{coNP}_{/\textsf{poly}}$. Additionally, we show that our constructions of witness encryption are plausibly secure against nondeterministic adversaries under a generalized notion of security in the spirit of Rudich's super-bits (RANDOM '97), which is crucial for demonstrating the hardness of $\textsf{Avoid}$ and $\textsf{RPP}$ against nondeterministic algorithms.
Qi Pang, Jinhao Zhu, Helen Möllering, Wenting Zheng, Thomas Schneider
Daniel J. Bernstein
This paper shows that 1 contradicts 2 and that 1 contradicts 3: the existing heuristics imply that hybrid primal key-recovery attacks are exponentially faster than standard non-hybrid primal key-recovery attacks against the LPR PKE with any constant error width. This is the first report since 2015 of an exponential speedup in heuristic non-quantum primal attacks against non-ternary LPR.
Quantitatively, for dimension n, modulus n^{Q_0+o(1)}, and error width w, a surprisingly simple hybrid attack reduces heuristic costs from 2^{(ρ+o(1))n} to 2^{(ρ-ρ H_0+o(1))n}, where z_0=2Q_0/(Q_0+1/2)^2, ρ=z_0 log_4(3/2), and H_0=1/(1+(lg w)/0.057981z_0). This raises the questions of (1) what heuristic exponent is achieved by more sophisticated hybrid attacks and (2) what impact hybrid attacks have upon concrete cryptosystems whose security analyses have ignored hybrid attacks, such as Kyber-512.
Huaxin Wang, Yiwen Gao, Yuejun Liu, Qian Zhang, Yongbin Zhou
Taipei Lu, Bingsheng Zhang, Lichun Li, Kui Ren
08 December 2023
Fully Parallel, One-Cycle Random Shuffling for Efficient Countermeasure in Post-Quantum Cryptography
Jong-Yeon Park, Dongsoo Lee, Seonggyeom Kim, Wonil lee, Bo Gyeong Kang, Kouichi Sakurai
Lev Soukhanov
There are other possible applications, requiring different design tradeoffs. Particularly interesting direction is a case with a swarm of collaborating provers, communicating over a peer-to-peer network - which requires to also optimize the amount of data exchanged between the participants of the swarm.
One notable such application is Ethereum's consensus, which requires to aggregate millions of signatures of individual validators.
In this technical note, we propose an informal notion of an end-to-end IVC scheme, which means that the amount of data that the prover needs exchange with the previous prover to continue the computation is small.
We explore the existing design space from this point of view, and suggest an approach to constructing such a scheme by combining the PlonK proof systemwith the recent Cyclefold construction.