IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
26 April 2024
Bernardo David, Rafael Dowsley, Anders Konring, Mario Larangeira
Nicholas Ngai, Ioannis Demertzis, Javad Ghareh Chamani, Dimitrios Papadopoulos
In this work, we address the scalability bottleneck of oblivious sort and shuffle by re-designing these approaches to achieve high efficiency in distributed multi-enclave environments. First, we propose a multi-threaded bitonic sort optimized for the distributed setting, making it the most performant oblivious sort for small number of enclaves (up to 4). For larger numbers of enclaves, we propose a novel oblivious bucket sort, which improves data locality and network consumption and outperforms our optimized distributed bitonic-sort by up to 5-6x. To the best of our knowledge, these are the first distributed oblivious TEE-based sorting solutions. For reference, we are able to sort 2 GiB of data in 1 second and 128 GiB in 53.4 seconds in a multi-enclave test. A fundamental building block of our oblivious bucket-sort is an oblivious shuffle that improves the prior state-of-the-art result (CCS'22) by up to 9.5x in the distributed multi-enclave setting---interestingly it is better by 10% even in the single-enclave/multi-thread setting.
Anant Sharma, Nupur Deshpande, Sanchita Ghosh, Sreetama Das, Shibdas Roy
Masaya Nanri, Octavio Perez Kempner, Mehdi Tibouchi, Masayuki Abe
Mercurial signatures are an extension of equivalence class signatures that allow malleability for the key space. Unfortunately, the most efficient construction to date suffers a severe limitation that limits their application: only a weak form of public key class-hiding is supported. In other words, given knowledge of the original signing key and randomization of the corresponding public key, it is possible to identify whether they are related.
In this work, we put forth the notion of interactive threshold mercurial signatures and show how they help to overcome the above-mentioned limitation. Moreover, we present constructions in the two-party and multi-party settings, assuming at least one honest signer. We also discuss related applications, including blind signatures, multi-signatures, and threshold ring signatures. To showcase the practicality of our approach, we implement the proposed constructions, comparing them against related alternatives.
Andrea Basso
We provide three constructions based on POKE: the first is a PKE protocol, which is one of the most compact post-quantum PKEs and possibly the most efficient isogeny-based PKE to date. We then introduce a validation technique to ensure the correctness of uniSIDH public keys: by combining the validation method with a POKE-based construction, we obtain a split KEM, a primitive that generalizes NIKEs and can be used to instantiate a post-quantum version of the Signal's X3DH protocol. The third construction builds upon the split KEM and its validation method to obtain a round-optimal verifiable OPRF. It is the first such construction that does not require more than $\lambda$ isogeny computations, and it is significantly more compact and more efficient than all other isogeny-based OPRFs.
Elif Ozbay Gurler, Huseyin Hisil
Roozbeh Sarenche, Svetla Nikova, Bart Preneel
Sebastian Bitzer, Jeroen Delvaux, Elena Kirshanova, Sebastian Maaßen, Alexander May, Antonia Wachter-Zeh
Consequently, using our template attack, we can practically recover an error vector in dimension n=2197 in a matter of seconds. Without side-channel information, such an instance has a complexity of around 88 bit. We also estimate how our template attack affects the security of the proposed McEliece parameter sets. Roughly speaking, even an error-prone leak of our Hamming weight information leads for n=3488 to a security drop of 89 bits.
Jingwen Chen, Qun Liu, Yanhong Fan, Lixuan Wu, Boyun Li, Meiqin Wang
Huiqiang Liang, Haining Lu, Geng Wang
Firstly, we propose three amortized efficient private comparison algorithms: TECMP, RDCMP and CDCMP, which are based on leveled homomorphic encryption. They are non-interactive, high precision (up to 26624-bit), many-to-many, and output expressive, achieving an amortized cost of less than 1 ms under 32-bit, which is an order of magnitude faster than the state-of-the-art. Secondly, we propose three batch PDTE schemes using our private comparison: TECMP-PDTE, RDCMP-PDTE and CDCMP-PDTE. Due to the batch operations, we utilized a clear rows relation (CRR) algorithm, which obfuscates the position and classification results of the different row data. Finally, in decision tree exceeding 1000 nodes with 16-bit each, the amortized runtime of TECMP-PDTE and RDCMP-PDTE both more than 56$\times$ faster than state-of-the-art, while the TECMP-PDTE with CRR still achieves 14$\times$ speedup. Even in a single row and a tree of fewer than 100 nodes with 64-bit, and the TECMP-PDTE maintains a comparable performance with the current work.
Yuncong Zhang, Shi-Feng Sun, Dawu Gu
Using $\mathsf{Losum}$ as a component, we then construct a new lookup argument, named $\mathsf{Locq}$, which enjoys a smaller proof size and a lower verification cost compared to the state of the arts $\mathsf{cq}$, $\mathsf{cq}$+ and $\mathsf{cq}$++. Specifically, the proving cost of $\mathsf{Locq}$ is comparable to $\mathsf{cq}$, keeping the advantage that the proving cost is independent of the table size after preprocessing. For verification, $\mathsf{Locq}$ costs four pairings, while $\mathsf{cq}$, $\mathsf{cq}$+ and $\mathsf{cq}$++ require five, five and six pairings, respectively. For proof size, a $\mathsf{Locq}$ proof consists of four $\mathbb{G}_1$ elements and one $\mathbb{G}_2$ element; when instantiated with the BLS12-381 curve, the proof size of $\mathsf{Locq}$ is $2304$ bits, while $\mathsf{cq}$, $\mathsf{cq}$+ and $\mathsf{cq}$++ have $3840$, $3328$ and $2944$ bits, respectively. Moreover, $\mathsf{Locq}$ is zero-knowledge as $\mathsf{cq}$+ and $\mathsf{cq}$++, whereas $\mathsf{cq}$ is not. $\mathsf{Locq}$ is more efficient even compared to the non-zero-knowledge (and more efficient) versions of $\mathsf{cq}$+ and $\mathsf{cq}$++.
Hongxiao Wang, Siu-Ming Yiu, Yanmin Zhao, Zoe L. Jiang, Min Xie
To break these limitations, we formalize the first system model and security model of MFC for circuits. Then, we target some specific properties of a new falsifiable assumption, i.e. the $\mathsf{BASIS}$ assumption proposed by Wee and Wu (EUROCRYPT '23) to construct the first lattice-based succinct mercurial functional commitment for circuits. To the application, we show that our constructions can be used to build the first lattice-based ZK-FEDB directly within the existing generic framework.
Hyeonbum Lee, Seunghun Paik, Hyunjung Son, Jae Hong Seo
Jialiu Cheng, Yi Wang, Rongmao Chen, Xinyi Huang
Foteini Baldimtsi, Jiaqi Cheng, Rishab Goyal, Aayush Yadav
24 April 2024
IIIT Bangalore
Closing date for applications:
Contact: ashish.choudhury@iiitb.ac.in
More information: https://www.iiitb.ac.in/courses/master-of-science-by-researchdoctor-of-philosophy
Warsaw, Poland, 14 July - 19 July 2024
23 April 2024
Surrey Centre for Cyber Security, University of Surrey, UK
Salary: 36,024 to 41,732 GBP
Closing Date: 13th May 2024
We are looking for a postdoc with expertise on electronic-voting or related topics. The successful post holder is expected to start 1 July 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).
Closing date for applications:
Contact: Cătălin Drăgan c.dragan@surrey.ac.uk
More information: https://jobs.surrey.ac.uk/Vacancy.aspx?id=13834&forced=2
Bosch Research, Renningen, Germany
Thus, we are looking for a highly motivated PhD candidate with a strong background in applied cryptography and preferably also MPC. The candidates should meet the following requirements:
- Education: Hold an M.Sc. degree (or equivalent) with excellent grades in IT security or computer science.
- Experience and Knowledge: Strong background in (applied) cryptography with a particular focus on cryptographic protocols/MPC, including security models and basic security proof techniques. Good software development/programming skills.
- Personality and Working Practice: Self-motivated and enthusiastic, independent, reliable, creative, and able to work in an international team with diverse background.
- Language: Fluent English language skills
- become a part of the team and advance research on MPC,
- develop novel approaches to improve the practical efficiency of actively secure MPC protocols,
- design efficient MPC protocols for diverse use-cases, and
- publish and present your results in top-tier journals and at conferences.
Closing date for applications:
Contact: Please submit your application, including your CV, transcripts of records from your Master studies, and a cover letter including your research background and research interest, via: https://smrtr.io/hmG3C
More information: https://youtu.be/OctvCi2pHJY
Hanoi, Vietnam, 3 December - 4 December 2024
Submission deadline: 30 July 2024
Notification: 5 September 2024