IACR News
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30 May 2023
Zhiyu Zhang, Siwei Sun, Caibing Wang, Lei Hu
ePrint ReportMariya Georgieva Belorgey, Sergiu Carpov, Nicolas Gama, Sandra Guasch, Dimitar Jetchev
ePrint ReportDominique Unruh
ePrint ReportUlrich Haböck
ePrint ReportFeng Hao, Samiran Bag, Liqun Chen, Paul C. van Oorschot
ePrint ReportAndrey Kim, Yongwoo Lee, Maxim Deryabin, Jieun Eom, Rakyong Choi
ePrint ReportThis approach allowed us to achieve the FHE scheme with the packed evaluation key transferring size of less than a Megabyte, which is an order of magnitude improvement compared to the best-known methods.
Qiqi Lai, Feng-Hao Liu, Anna Lysyanskaya, Zhedong Wang
ePrint ReportTo achieve this, we make the following contributions. By distilling prior design insights, we propose a new primitive to instantiate \emph{signature with protocols}, called commit-transferrable signature (\CTS). When combined with a multi-theorem straight-line extractable non-interactive zero-knowledge proof of knowledge (\NIZKPoK), $\CTS$ gives a modular approach to construct anonymous credentials. We then show efficient instantiations of $\CTS$ and the required \NIZKPoK from lattices, which are believed to be post-quantum hard. Finally, we propose concrete parameters for the $\CTS$, \NIZKPoK, and the overall Anonymous Credentials, based on Module-\SIS~and Ring-\LWE. This would serve as an important guidance for future deployment in practice.
Jack Doerner, Yashvanth Kondi, Eysa Lee, abhi shelat
ePrint ReportPascal Bemmann, Sebastian Berndt, Denis Diemert, Thomas Eisenbarth, Tibor Jager
ePrint ReportMiranda Christ, Sam Gunn, Or Zamir
ePrint ReportTo this end we introduce a cryptographically-inspired notion of undetectable watermarks for language models. That is, watermarks can be detected only with the knowledge of a secret key; without the secret key, it is computationally intractable to distinguish watermarked outputs from those of the original model. In particular, it is impossible for a user to observe any degradation in the quality of the text. Crucially, watermarks should remain undetectable even when the user is allowed to adaptively query the model with arbitrarily chosen prompts. We construct undetectable watermarks based on the existence of one-way functions, a standard assumption in cryptography.
Sivanarayana Gaddam, Ranjit Kumaresan, Srinivasan Raghuraman, Rohit Sinha
ePrint ReportIn this paper, we address the above by showing the first protocols for fair secure computation in the multi-blockchain setting. More concretely, in a $n$-party setting where at most $t < n$ parties are corrupt, our protocol for fair secure computation works as long as (1) $t$ parties have access to a TEE (e.g., Intel SGX), and (2) each of the above $t$ parties are on some blockchain with each of the other parties. Furthermore, only these $t$ parties need write access on the blockchains.
In an optimistic setting where parties behave honestly, our protocol runs completely off-chain.
Sebastian Angel, Aditya Basu, Weidong Cui, Trent Jaeger, Stella Lau, Srinath Setty, Sudheesh Singanamalla
ePrint ReportAnton Wahrstätter, Liyi Zhou, Kaihua Qin, Davor Svetinovic, Arthur Gervais
ePrint ReportThis paper presents an in-depth longitudinal study of the Ethereum block construction market, spanning from the introduction of PoS and PBS in September 2022 to May 2023. We analyze the market shares of builders and relays, their temporal changes, and the financial dynamics within the PBS system, including payments among builders and block proposers---commonly referred to as bribes. We introduce an MEV-time law quantifying the expected MEV revenue wrt. the time elapsed since the last proposed block. We provide empirical evidence that moments of crisis (e.g. the FTX collapse, USDC stablecoin de-peg) coincide with significant spikes in MEV payments compared to the baseline.
Despite the intention of the PBS architecture to enhance decentralization by separating actor roles, it remains unclear whether its design is optimal. Implicit trust assumptions and conflicts of interest may benefit particular parties and foster the need for vertical integration. MEV-Boost was explicitly designed to foster decentralization, causing the side effect of enabling risk-free sandwich extraction from unsuspecting users, potentially raising concerns for regulators.
Jeongeun Park, Sergi Rovira
ePrint ReportLaura Hetz, Thomas Schneider, Christian Weinert
ePrint ReportIn our work, we make significant steps towards truly practical large-scale mobile private contact discovery. For this, we combine and substantially optimize the unbalanced PSI protocol of Kales et al. (USENIX Security '19) and the private information retrieval (PIR) protocol of Kogan and Corrigan-Gibbs (USENIX Security '21). Our resulting protocol has a total communication overhead that is sublinear in the size of the server's user database and also has sublinear online runtimes. We optimize our protocol by introducing database partitioning and efficient scheduling of user queries. To handle realistic change rates of databases and contact lists, we propose and evaluate different possibilities for efficient updates. We implement our protocol on smartphones and measure online runtimes of less than 2s to query up to 1024 contacts from a database with more than two billion entries. Furthermore, we achieve a reduction in setup communication up to factor 32x compared to state-of-the-art mobile private contact discovery protocols.
Zhengjun Cao, Lihua Liu
ePrint Report26 May 2023
Santa Barbara, USA, 20 August 2023
Event CalendarSubmission deadline: 15 June 2023
University of St.Gallen, Switzerland
Job PostingThe student is expected to work on topics that include security and privacy issues in authentication. More precisely, the student will be working on investigating efficient and privacy-preserving authentication that provides: i) provable security guarantees, and ii) rigorous privacy guarantees.
Key Responsibilities:
- Perform exciting and challenging research in the domain of information security and cryptography.
- Support and assist in teaching computer security and cryptography courses.
- The PhD student is expected to have a MSc degree or equivalent, and strong background in cryptography, network security and mathematics.
- Experience in one or more domains such as cryptography, design of protocols, secure multi-party computation and differential privacy is beneficial.
- Excellent programming skills.
- Excellent written and verbal communication skills in English
The starting date for the position is flexible and come with a very competitive salary. The selection process runs until the suitable candidate has been found.
Closing date for applications:
Contact:
Eriane Breu, eriane.breu@unisg.ch (Administrative matters)
Prof. Katerina Mitrokotsa, katerina.mitrokotsa@unisg.ch (Research related questions)
University of St.Gallen, Switzerland
Job PostingOur research interests are centered around information security and applied cryptography, with the larger goal of safeguarding communications and providing strong privacy guarantees. We are active in several areas, a subset of which include:
- Verifiable computation
- Secure, private and distributed aggregation
- Secure multi-party computation
- Privacy-preserving biometric authentication
- Anonymous credentials
- Distributed and privacy-preserving authentication
The starting date for the position is flexible and come with a very competitive salary. The selection process runs until the suitable candidate has been found. The University of St.Gallen conducts excellent research with international implications. The city of St.Gallen is located one hour from Zurich and offers a high quality of life.
Closing date for applications:
Contact:
Eriane Breu, eriane.breu@unisg.ch (Administrative matters)
Prof. Katerina Mitrokotsa, katerina.mitrokotsa@unisg.ch (Research related questions)
University of Klagenfurt; Klagenfurt, Austria
Job PostingThe University of Klagenfurt in southern Austria is looking for a Professor of Cybersecurity:
https://jobs.aau.at/en/job/professor-of-cybersecurity/
Application deadline is 18 June 2023.
Closing date for applications:
Contact: Wolfgang Faber
More information: https://jobs.aau.at/en/job/professor-of-cybersecurity/