IACR News
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02 February 2024
Jonathan Komada Eriksen, Antonin Leroux
Charlotte Hoffmann, Pavel Hubáček, Svetlana Ivanova
In this work, we introduce two batch PoEs that outperform both proposals of Rotem and we evaluate their practicality. First, we show that the two batch PoEs of Rotem can be combined to improve the overall efficiency by at least a factor of two. Second, we revisit the work of Bellare, Garay, and Rabin (EUROCRYPT 1998) on batch verification of digital signatures and show that, under the low order assumption, their bucket test can be securely adapted to the setting of groups of unknown order. The resulting batch PoE quickly outperforms the state of the art in the expected number of group multiplications with the growing number of instances, and it decreases the cost of batching by an order of magnitude already for hundreds of thousands of instances. Importantly, it is the first batch PoE that significantly decreases both the proof size and complexity of verification. Our experimental evaluations show that even a non-optimized implementation achieves such improvements, which would match the demands of real-life systems requiring large-scale PoE processing.
Finally, even though our proof techniques are conceptually similar to Rotem, we give an improved analysis of the application of the low order assumption towards secure batching of PoE instances, resulting in a tight reduction, which is important when setting the security parameter in practice.
Maria Corte-Real Santos, Craig Costello, Benjamin Smith
Xuanming Liu, Zhelei Zhou, Yinghao Wang, Bingsheng Zhang, Xiaohu Yang
In this work, we address this issue by lifting a zk-SNARK called Libra (Crypto 2019) to a collaborative zk-SNARK and achieve a fully distributed proof generation, where all servers take roughly the same portion of the total workload. Further, our protocol can be adapted to be secure against a malicious adversary by incorporating some verification mechanisms. With 128 consumer machines and a 4Gbps network, we successfully generate a proof for a data-parallel circuit containing $2^{23}$ gates in merely 2.5 seconds and take only 0.5 GB memory for each server. This represents a $19\times$ speed-up, compared to a local Libra prover. Our benchmark further indicates an impressive 877$\times$ improvement in running time and a 992$\times$ enhancement in communication compared to the implementation in previous work. Furthermore, our protocol is capable of handling larger circuits, making it scalable in practice.
Xiaohai Dai, Zhaonan Zhang, Jiang Xiao, Jingtao Yue, Xia Xie, Hai Jin
To reduce latency, we propose GradedDAG, a new DAG-based BFT consensus protocol based on our adapted RBC called Graded RBC (GRBC) and the Consistent Broadcast (CBC), with each wave consisting of only one GRBC round and one CBC round. Through GRBC, a replica can deliver data with a grade of 1 or 2, and a non-faulty replica delivering the data with grade 2 can ensure that more than 2/3 of replicas have delivered the same data. Meanwhile, through CBC, data delivered by different non-faulty replicas must be identical. In each wave, a block in the GRBC round will be elected as the leader. If a leader block has been delivered with grade 2, it and all its ancestor blocks can be committed. GradedDAG offers a good-case latency of 4 communication steps and an expected worst latency of 7.5 communication steps, significantly lower than the state-of-theart. Experimental results demonstrate GradedDAG’s feasibility and efficiency.
Gilad Asharov, Koki Hamada, Dai Ikarashi, Ryo Kikuchi, Ariel Nof, Benny Pinkas, Junichi Tomida
Both JOIN and GROUP-BY involve many variants, and we design protocols for several common procedures. In particular, we propose a novel group-by-median protocol that has not been known so far. Our protocols rely on sorting protocols, and work in the honest majority setting and against malicious adversaries. To the best of our knowledge, this is the first implementation of JOIN and GROUP-BY protocols secure against a malicious adversary.
Binbin Tu, Min Zhang, Yu Chen
In this paper, we propose efficient ECDSA-based adaptor signature schemes and give security proofs based on ECDSA. In our schemes, the zero-knowledge proofs in the pre-signing phase can be generated in a batch and offline. Meanwhile, the online pre-signing algorithm is similar to the ECDSA signing algorithm and can enjoy the same efficiency as ECDSA. In particular, considering specific verification scenarios, such as (batched) atomic swaps, our schemes can reduce the number of zero-knowledge proofs in the pre-signing phase to one, independent of the number of participants. Last, we conduct an experimental evaluation, demonstrating that the performance of our ECDSA-based adaptor signature reduces online pre-signing time by about 60% compared with the state-of-the-art ECDSA-based adaptor signature.
David Heath
We construct arithmetic garbled circuits from circular correlation robust hashes, the assumption underlying the celebrated Free XOR garbling technique. Let $\lambda$ denote a computational security parameter, and consider the integers $\mathbb{Z}_m$ for any $m \geq 2$. Let $\ell = \lceil \log_2 m \rceil$ be the bit length of $\mathbb{Z}_m$ values. We garble arithmetic circuits over $\mathbb{Z}_m$ where the garbling of each gate has size $O(\ell \cdot \lambda)$ bits. Constrast this with Boolean-circuit-based arithmetic, requiring $O(\ell^2\cdot \lambda)$ bits via the schoolbook multiplication algorithm, or $O(\ell^{1.585}\cdot \lambda)$ bits via Karatsuba's algorithm.
Our arithmetic gates are compatible with Boolean operations and with Garbled RAM, allowing to garble complex programs of arithmetic values.
01 February 2024
Karlsruhe, Germany, 14 March - 15 March 2024
Submission deadline: 18 February 2024
Notification: 26 February 2024
Stanford, USA, 14 August - 16 August 2024
Submission deadline: 10 March 2024
Notification: 31 May 2024
University of Amsterdam, The Netherlands
Our modern society relies upon numerous electronic devices that use encryption to communicate and operate securely. However, even strong cryptography can break when the device hardware is attacked. Thus, the University of Amsterdam is looking for a strong MSc graduate that is interested in Side-Channel Analysis, Hardware Security and Cryptographic Implementations.
What are you going to do?
Apply using the link:
https://vacatures.uva.nl/UvA/job/PhD-in-Side-Channel-Analysis/786914702/
Closing date for applications:
Contact: Kostas Papagiannopoulos, k.papagiannopoulos@uva.nl, kostaspap88@gmail.com
More information: https://vacatures.uva.nl/UvA/job/PhD-in-Side-Channel-Analysis/786914702/
Brandenburg University of Technology Cottbus-Senftenberg
- Privacy-enhancing technologies in cyber-physical systems.
- AI-based network attack detection and simulation
- AI-enabled penetration testing
Closing date for applications:
Contact: Ivan Pryvalov (ivan.pryvalov@b-tu.de)
School of Computing and Information Technology, University of Wollongong, Australia
Closing date for applications:
Contact: Dr. Zuoxia Yu (given name_first name at uow.edu.au)
TU Wien, Security and Privacy Research Unit
Your profile:
- Master degree in computer science or equivalent (degree completion by employment start)
- Excellent English, communication, and teamwork skills
- Background in formal methods (e.g., automated reasoning, type systems, or proof assistants) or cryptography
- Experience in research is a plus
- A job in an internationally renowned group, which regularly publishes in top security venues, and consists of an international, diverse, and inclusive team with expertise in formal methods, cryptography, security, privacy, and blockchains
- Diverse research topics in formal methods for security and privacy, with a specific focus on cryptographic protocols and blockchains
- An international English-speaking environment (German not required)
- A competitive salary
- Flexible hours
- Motivation letter
- Bachelor/Master’s transcripts
- Publication list (if available)
- Curriculum vitae
- Contact information for two referees
Closing date for applications:
Contact: Univ.-Prof. Dr. Matteo Maffei
More information: https://tools.spycode.at/recruiting/call/5
COSIC, KU Leuven, Belgium
Closing date for applications:
Contact: Bart.Preneel@kuleuven.be, Vincent.Rijmen@kuleuven.be
University of Surrey, UK
We are looking for a postdoc with expertise on electronic-voting or related topics. The successful post holder is expected to start 1 May 2024 or as soon as possible thereafter and will run until 31st October 2026. The position will be based in the Department of Computer Science and its highly regarded Surrey Centre for Cyber Security (SCCS), working with Dr. Cătălin Drăgan.
The Surrey Centre for Cyber Security (SCCS) is a widely recognized centre of excellence for cyber security research and teaching. There are approximately 17 permanent academic members and 15 non-academic researchers with expertise on voting, formal modelling and verification, applied cryptography, trust systems, social media, communication and networks, and blockchain and distributed ledger technologies over key sectors such as government, finance, communications, transport and cross-sector technologies.
Qualifications:
- We are looking for applicants that demonstrate strong research and analytical skills, have strong communication skills and enthusiasm for developing their own research ideas.
- Applicants should have expertise in one of the following areas: e-voting, or formal verification of cryptographic protocols, or provable security.
- A PhD in Computer Science, Mathematics, or other closely related area (or be on course of getting one very soon at the time of application).
To apply use https://jobs.surrey.ac.uk/Vacancy.aspx?id=13834
For informal enquiries and further information please contact Dr. Cătălin Drăgan.Closing date for applications:
Contact: Dr. Cătălin Drăgan c.dragan@surrey.ac.uk
More information: https://jobs.surrey.ac.uk/Vacancy.aspx?id=13834
Input-Output Global
As Cryptographic Engineering Lead you are responsible for defining the roadmap for cryptographic innovation consistent with the requirements of different projects that are developed in the company and delivering of the cryptographic primitives implementation.
Duties
Key Competencies
Education / Experience
Closing date for applications:
Contact: marios.nicolaides@iohk.io
More information: https://apply.workable.com/io-global/j/A7EE304D9F/
SUTD, Singapore
* A PhD degree in computer science or related fields
* Good background in cybersecurity and digital forensics.
* Experience in biometric-based authentication for smartphone users.
* Practical experience in machine learning and AI.
* Strong analytical skill.
* Publication records in *top* cybersecurity conferences/journals.
* Good programming skill in C/C++ and Python/Java.
* Excellent communication and writing skills in English.
* Great team player.
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 [jianying_zhou@sutd.edu.sg].
Closing date for applications:
Contact: Prof. Jianying Zhou [jianying_zhou@sutd.edu.sg].
More information: http://jianying.space/