IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
30 December 2020
Fan Peng, Hao Chen, Chang-An Zhao
In this paper it is proved that almost all subsets of $u \in [T,T+g-1]$ players have no information of the secret and almost all subsets of $u \in [T+g,T+2g-1]$ players can reconstruct the secret when the size $q$ goes to the infinity and the genus satisfies $\lim \frac{g}{\sqrt{q}}=0$. Then algebraic geometric secretsharing schemes over large finite fields are asymptotically threshold in this case. We also analyze the case when the size $q$ of the base field is fixed and the genus goes to the infinity.
Guoai Xu, Jiangtao Yuan, Guosheng Xu
Aljosha Judmayer, Nicholas Stifter, Alexei Zamyatin, Itay Tsabary, Ittay Eyal, Peter Gazi, Sarah Meiklejohn, Edgar Weippl
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Submission deadline: 31 July 2021
University of Erlangen
What we expect:
- A PhD degree in Cryptography
- Strong publication record
- Research statement
- Ideally two reference letters
- High motivation
Closing date for applications:
Contact: Dominique Schröder
Clemson University
Closing date for applications:
Contact: Felice Manganiello
More information: https://www.mathjobs.org/jobs/list/17017
National Sun Yat-sen University, Department of Computer Science and Engineering, Kaohsiung, Taiwan
Closing date for applications:
Contact: Prof. S.R. Kuang, Email: srkuang@cse.nsysu.edu.tw, TEL:+886-7-5252000 ext. 4340, FAX:+886-7-5254301
More information: https://cse.nsysu.edu.tw/index.php?Lang=en
New York University Abu Dhabi
Closing date for applications:
Contact: Christina Poepper, christina.poepper@nyu.edu
More information: https://apply.interfolio.com/77776
NCC Group North America
NCC Group Crypto Services is hiring interns for summer 2021! We're a small-ish team auditing applied crypto and doing research in the field. If you like cryptography and security, and would like to pursue a research project in any of the applied crypto areas, such as (but not limited to):
- cryptographic implementations (cryptographic protocols or primitives block ciphers, elliptic cures, hash functions, lightweight crypto, post-quantum crypto)
- cryptocurrencies (audits of novel consensus algorithms, privacy preserving technologies in this space, etc.)
- audits of existing cryptographic software
The position will possibly be fully remote. The intern will get a feel of what crypto consulting looks like and do a research project with the help of a member of NCC Group CS team. Only candidates with legal permission to work in US or Canada would be considered due to short-term nature of the job.
Closing date for applications:
Contact: cs-intern-jobs@nccgroup.com
More information: https://www.nccgroup.com/us/our-services/cyber-security/specialist-practices/cryptography-services/
Duc-Phong Le, Binh P Nguyen
29 December 2020
Sri Aravinda Krishnan Thyagarajan, Giulio Malavolta
In this work, we investigate whether we can construct PCNs assuming the minimal ability of a blockchain to verify a digital signature, for any signature scheme. In answering this question in the affirmative, we introduce the notion of lockable signatures, which constitutes the cornerstone of our PCN protocols. Our approach is generic and the PCN protocol is compatible with any digital signature scheme, thus inheriting all favorable properties of the underlying scheme that are not offered by Schnorr/ECDSA (e.g.\ aggregatable signatures or post-quantum security).
While the usage of generic cryptographic machinery makes our generic protocol impractical, we view it as an important feasibility result as it may serve as the basis for constructing optimized protocols for specific signature schemes. To substantiate this claim, we design a highly efficient PCN protocol for the special case of Boneh-Lynn-Shacham (BLS) signatures. BLS signatures enjoy many unique features that make it a viable candidate for a blockchain, e.g. short, unique, and aggregatable signatures. Yet, prior to our work, no PCN was known to be compatible with it (without requiring an advanced scripting language). The cost of our PCN is dominated by a handful of calls to the BLS algorithms. Our concrete evaluation of these basic operations shows that users with commodity hardware can process payments with minimal overhead.
Jiangtao Yuan, Jing Yang, Guoai Xu, Xingxing Jia, Chennyu Wang
Jonathan Takeshita, Ryan Karl, Ting Gong, Taeho Jung
Mihai-Andrei Costandache, Marian-Stefan Mihalache, Emil Simion
27 December 2020
Amar Bapić, Enes Pasalic
Daniel J. Bernstein
Shumo Chu, Qiudong Xia, Zhenfei Zhang
Wen-jie Lu, Zhicong Huang, Cheng Hong, Yiping Ma, Hunter Qu
Alexander R. Block, Simina Branzei, Hemanta K. Maji, Himanshi Mehta, Tamalika Mukherjee, Hai H. Nguyen
Our work encodes joint probability distributions and Boolean functions as equivalent bipartite graphs and studies the $P_4$-free partition and cover numbers of these graphs. Leveraging this connection, we present representative applications of these graph properties and their estimates to information-theory and circuit complexity. For applications in information theory, we consider a system where a setup samples from a joint distribution and gives the participants, Alice and Bob, their portion from this joint sample. The objective of Alice and Bob is to non-interactively establish a shared key and extract the left-over entropy from their portion of the samples as independent private randomness. A genie, who observes the joint sample, provides an appropriate assistance to help Alice and Bob with their objective. Lower bounds to the minimum size of the genie's assistance translates into communication and cryptographic lower bounds. We show that (the $\log_2$ of) the $P_4$-free partition number of a graph encoding the joint distribution that the setup uses is equivalent to the size of the genie's assistance. Consequently, the joint distributions corresponding to the bipartite graphs constructed above with high $P_4$-free partition number correspond to joint distributions requiring more assistance from the genie.
As a representative application in communication complexity, we study communication complexity of non-deterministic protocols augmented by access to the equality oracle at the output. We show that (the $\log_2$ of) the $P_4$-free cover number of the bipartite graph encoding a Boolean function $f$ is equivalent to the minimum size of the non-deterministic input required by the parties (referred to as the communication complexity of $f$ in this model). Consequently, the functions corresponding to the bipartite graphs with high $P_4$-free cover number have high communication complexity. Furthermore, there are functions with communication complexity close to the \naive protocol where the non-deterministic input reveals the input of a party. Finally, the access to the equality oracle reduces the communication complexity of computing set intersection and disjointness by a constant factor in contrast to the model where parties do not have access to the equality oracle. In the case of computing the inequality function, we show an exponential reduction in the communication complexity.