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15 July 2022
Haining Fan
We also show that ``finding common subexpressions'' performs better than ``the refined identity'' in 4-term formula: we reduce the number of XOR gates given by Cenk, Hasan and Negre in IEEE T. Computers in 2014.
James Bell, Adria Gascon, Badih Ghazi, Ravi Kumar, Pasin Manurangsi, Mariana Raykova, Phillipp Schoppmann
14 July 2022
Kalle Ngo, Ruize Wang, Elena Dubrova, Nils Paulsrud
Wonseok Choi, Jooyoung Lee, Yeongmin Lee
A natural question is whether one can construct a pseudorandom function (PRF) beyond the block and the tweak length bounds using a small number of calls to the underlying tweakable permutations. As a positive answer to this question, we propose two PRF constructions based on tweakable permutations, dubbed $\mathsf{XoTP1}_c$ and $\mathsf{XoTP2}_c$, respectively. Both constructions are parameterized by $c$, giving a $(t+n-c)$-to-$n$ bit PRF.
When $t<2n$, $\mathsf{XoTP1}_{\frac{t}{2}}$ becomes an $(n+\frac{t}{2})$-to-$n$ bit pseudorandom function, which is secure up to $2^{n+\frac{t}{2}}$ queries. $\mathsf{XoTP2}_{\frac{t}{3}}$ is even better, giving an $(n+\frac{2t}{3})$-to-$n$ bit pseudorandom function, which is secure up to $2^{n+\frac{2t}{3}}$ queries, when $t<3n$. These PRFs provide security beyond the block and the tweak length bounds, making two calls to the underlying tweakable permutations.
In order to prove the security of $\mathsf{XoTP1}$ and $\mathsf{XoTP2}$, we firstly extend Mirror theory to $q \gg 2^n$, where $q$ is the number of equations. From a practical point of view, our constructions can be used to construct TBC-based MAC finalization functions and CTR-type encryption modes with stronger provable security compared to existing schemes.
Ashish Choudhury
Melissa Azouaoui, Yulia Kuzovkova, Tobias Schneider, Christine van Vredendaal
Ahmad Al Badawi, Jack Bates, Flavio Bergamaschi, David Bruce Cousins, Saroja Erabelli, Nicholas Genise, Shai Halevi, Hamish Hunt, Andrey Kim, Yongwoo Lee, Zeyu Liu, Daniele Micciancio, Ian Quah, ...
Keegan Ryan, Nadia Heninger
Ashish Choudhury, Arpita Patra
Haetham AL ASWAD, Cécile PIERROT
Jianfang "Danny" Niu
Shweta Agrawal, Jung Hee Cheon, Hyeongmin Choe, Damien Stehlé, Anshu Yadav
In this work, we provide an efficient, round-optimal (two-round) blind signature scheme from the hardness of the discrete log (DL) problem {\it and} the learning with errors problem in the (non black-box) random oracle model. Our construction enjoys {\it post-quantum} blindness and does not rely on idealizations such as the algebraic group model or generic group model. We provide a concrete instantiation of our construction. Specifically, our blind signature size and verification time is the same as base Schnorr signature scheme which is used for a building block, making the signature extremely short and the verification extremely fast.
To the best of our knowledge, ours is the first efficient candidate from standard assumptions which simultaneously achieves (very) short signatures, fast verification time, post-quantum blindness and round optimality.
Carlo Brunetta, Hans Heum, Martijn Stam
Tymoteusz Chojecki, Vasyl Ustimenko
Xiao Liang, Omkant Pandey, Takashi Yamakawa
We achieve our results through a new technique for constant-round non-malleable commitments which is easier to use in the post-quantum setting. The technique also yields an almost elementary proof of security for constant-round non-malleable commitments in the classical setting, which may be of independent interest.
As an application, when combined with existing work, our results yield the first constant-round post-quantum secure multiparty computation under the $\mathit{polynomial}$ hardness of quantum fully-homomorphic encryption and quantum learning with errors.
Marc Fischlin, Felix Rohrbach, Tobias Schmalz
Besides formalizing the notion of the universal random oracle model we show that the model is asymptotically equivalent to Unruh's auxiliary-input random oracle model (Crypto 2007). In Unruh's model the adversary receives some inefficiently computed information about the random oracle as extra input. Noteworthy, while security in the universal random oracle model implies security in the auxiliary-input random oracle model tightly, the converse implication introduces an inevitable security loss. This implies that the universal random oracle model provides stronger guarantees in terms of concrete security. Validating the model we finally show, via a direct proof with concrete security, that a universal random oracle is one-way.
Indian Institute of Technology Kharagpur
Lab websites:
1. http://cse.iitkgp.ac.in/resgrp/seal/
2. https://sites.google.com/view/hardware-and-cyber-physical-se/home?authuser=1
3. Youtube Channel: https://www.youtube.com/channel/UC-343QYYo1bhSGW1JLXDANA
Closing date for applications:
Contact: Prof Debdeep Mukhopadhyay Computer Science and Engineering Indian Institute of Technology Kharagpur West Bengal, 721302, India
More information: http://www.iitkgp.ac.in/temporary-jobs
Ruhr-University Bochum and Max Planck Institute for Security and Privacy
- Security of smart contracts
- Formal verification of smart contracts
- Security of blockchain consensus protocols
- A Master’s degree or equivalent (or be close to completing one) in computer science, mathematics, or related fields.
- Outstanding candidates with a Bachelor’s degree will also be considered.
- Excellent communication/writing skills in English; knowledge of German is not required.
- An outstanding track record in classes related to IT security, cryptography, or formal methods/mathematics.
The positions are fully funded (100%) and paid according to the E-13 pay category. To apply, please send an email to both Dr. Schneidewind and Prof. Dr. Karame with the following documents in a single PDF:
- CV, including transcripts.
- A brief cover letter describing your research interests.
- Contact details of 2-3 potential references
Closing date for applications:
Contact: Prof. Dr. Ghassan Karame (ghassan.karame@rub.de) and Dr. Clara Schneidewind (clara.schneidewind@mpi-sp.org)
More information: https://informatik.rub.de/infsec/
Postdoctoral Researcher and Research Fellow positions in ICT (Cybersecurity, Cryptography, and More)
Helsinki Institute for Information Technology, Helsinki, Finland
The Helsinki Institute for Information Technology (HIIT) in cooperation with the Finnish Center for Artificial Intelligence (FCAI) invite applications for Postdoctoral Researchers for a term of two years with the possibility of a one year extension. HIIT offers a HIIT Postdoctoral Fellow position for two years, with the possibility of a one year extension. For more senior candidates, HIIT offers a HIIT Research Fellow position of three years, with the possibility of a two year extension. The length of the contract as well as the starting and ending dates are negotiable.
All excellent researchers in any area of ICT can be considered, but priority is given to candidates who support one (or more) of the HIIT strategic focus areas:
- Artificial Intelligence
- Computational Health
- Cybersecurity
- Data Science
- Foundations of Computing
Closing date for applications:
Contact: Russell W. F. Lai (russell.lai at aalto dot fi)
More information: https://www.aalto.fi/en/open-positions/postdoctoral-researcher-and-research-fellow-positions-in-ict
Indian Institute of Science (IISc), Bangalore, India
The applicant is expected to have completed a PhD degree (recently) in Cryptography or a related subject with strong publication records. A background in theoretical aspects of secure multiparty computation and/or experience in coding for practical aspects of secure computation is expected. Postdoctoral fellows are expected to actively interact with PhD students and contribute to the lab's projects. The tenure of the position is for one year and can be extended further.
You can apply through and find further details regarding opportunities at CrIS here - https://www.csa.iisc.ac.in/~cris/opportunities.html
Closing date for applications:
Contact: Professor Arpita Patra
More information: https://www.csa.iisc.ac.in/~cris/about.html