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06 May 2021
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Technology Innovation Institute (TII) - Abu Dhabi, UAE
Technology Innovation Institute (TII) is a publicly funded research institute, based in Abu Dhabi, United Arab Emirates. It is home to a diverse community of leading scientists, engineers, mathematicians, and researchers from across the globe, transforming problems and roadblocks into pioneering research and technology prototypes that help move society ahead.
Cryptography Research Centre
In our connected digital world, secure and reliable cryptography is the foundation of digital information security and data integrity. We address the world’s most pressing cryptographic questions. Our work covers post-quantum cryptography, lightweight cryptography, cloud encryption schemes, secure protocols, quantum cryptographic technologies and cryptanalysis.
Position: Senior MPC Researcher
Skills required for the job
Qualifications
Closing date for applications:
Contact: Mehdi Messaoudi - Talent Acquisition Manager
More information: https://career22.sapsf.com/sfcareer/jobreqcareer?jobId=1323&company=technolo01
Technology Innovation Institute (TII) - Abu Dhabi, UAE
Technology Innovation Institute (TII) is a publicly funded research institute, based in Abu Dhabi, United Arab Emirates. It is home to a diverse community of leading scientists, engineers, mathematicians, and researchers from across the globe, transforming problems and roadblocks into pioneering research and technology prototypes that help move society ahead.
Cryptography Research Centre
In our connected digital world, secure and reliable cryptography is the foundation of digital information security and data integrity. We address the world’s most pressing cryptographic questions. Our work covers post-quantum cryptography, lightweight cryptography, cloud encryption schemes, secure protocols, quantum cryptographic technologies and cryptanalysis.
Position: Senior FHE Researcher
Skills required for the job
Qualifications
Closing date for applications:
Contact:
Mehdi Messaoudi - Talent Acquisition Manager
More information: https://careers.tii.ae/job/Abu-Dhabi-Senior-FHE-Researcher/571308722/
IMDEA Software Institute, Madrid, Spain
Closing date for applications:
Contact: Alexey Gotsman (https://software.imdea.org/~gotsman/)
More information: https://software.imdea.org/open_positions/2021-05-postdoc-blockchains.html
Clemson University
Closing date for applications:
Contact: Felice Manganiello
More information: http://apply.interfolio.com/87198
04 May 2021
Onur Gunlu, Ueli Maurer, Joao Ribeiro
Jaipur, India, 12 December - 15 December 2021
Submission deadline: 7 September 2021
Notification: 12 October 2021
Seoul National University of Science and Technology, Seoul, South Korea
Current Research Directions:
Required Qualifications:
Appointment term: 1 year commitment to postdoctoral training is expected (can be extended depending on performance).
Appointment start date: 2021.09.01 (if possible, is it advisable to start in June or July).
Required Application Materials:
Closing date for applications:
Contact: Interested candidates should email their application materials to professor Changhoon Lee (chlee@seoultech.ac.kr) before May 31.
More information: https://cis.seoultech.ac.kr
The Knowledge Hub Universities
Closing date for applications:
Contact: Karim.ghaleb@elsewedyedu.com
More information: https://careers.tkh.edu.eg/en/egypt/jobs/head-of-school-computing-4286023/
Lorenz Panny
StarkWare
03 May 2021
Abhrajit Sengupta, Nimisha Limaye, Ozgur Sinanoglu
Leo de Castro, Antigoni Polychroniadou
Our verifiability method is lightweight in two ways. Firstly, it is concretely very efficient, making use of only symmetric key operations and no MPC or linear PCP techniques. For security parameter $\lambda$, our verification procedure is simply to check if two $2\lambda$-bit strings match. Secondly, our verification procedure is essentially unconstrained. It will verify that distributed point function (DPF) shares correspond to some point function irrespective of the output group size, the structure of the DPF output, or the set of points on which the DPF must be evaluated. This is in stark contrast with prior works, which depended on at least one and often all three of these factors. In addition, we give a novel method for packing DPFs into shares of a multi-point function that allows for the number of nonzero points in the multi-point function to grow without growing the evaluation time. We also show how our verification scheme carries over to the multi-point setting. We give an implementation of our verifiable distributed point functions and our verifiable distributed multi-point function.
Joseph Jaeger, Fang Song, Stefano Tessaro
We consider the latter approach -- in particular, analyzing the security of the FX and double encryption constructions. Classically, these constructs were considered as key-length extension techniques for DES. FX was proven to be a secure key-length extension technique, while double encryption was shown to be no more secure than single encryption due to a meet-in-the-middle attack. In this work we provide positive results, with concrete and tight bounds, for the security of both of these constructions against quantum attackers in ideal models.
For FX, we consider security in the so-called "Q1 model," a natural model in which the attacker has quantum access to the ideal primitive, but only classic access to FX. We provide two partial results for FX in this model. The first establishes the security of FX against non-adaptive attackers. The second establishes security against fully adaptive attackers when considering a variant of FX using a random oracle in place of an ideal cipher. This result relies on the techniques of Zhandry (CRYPTO '19) for lazily sampling a quantum random oracle and are thus hard to extend to the true FX construction because it is currently unknown if a quantum random permutation can be lazily sampled. To the best of our knowledge, this result also is the first to introduce techniques to handle Q1 security in ideal models without analyzing the classical and quantum oracles separately, which may be of broader interest.
For double encryption we apply a technique of Tessaro and Thiruvengadam (TCC '18) to establish that security reduces to the difficulty of solving the list disjointness problem, which we are able to reduce through a chain of results to the known quantum difficulty of the element distinctness problem.
Itai Dinur
In this paper, we devise a concretely efficient polynomial method-based algorithm for solving multivariate equation systems over $\mathbb{F}_2$. We analyze our algorithm's performance for solving random equation systems, and bound its complexity by about $n^2 \cdot 2^{0.815n}$ bit operations for $d = 2$ and $n^2 \cdot 2^{\left(1 - 1/2.7d\right) n}$ for any $d \geq 2$.
We apply our algorithm in cryptanalysis of recently proposed instances of the Picnic signature scheme (an alternate third-round candidate in NIST's post-quantum standardization project) that are based on the security of the LowMC block cipher. Consequently, we show that 2 out of 3 new instances do not achieve their claimed security level. As a secondary application, we also improve the best-known preimage attacks on several round-reduced variants of the Keccak hash function.
Our algorithm combines various techniques used in previous polynomial method-based algorithms with new optimizations, some of which exploit randomness assumptions about the system of equations. In its cryptanalytic application to Picnic, we demonstrate how to further optimize the algorithm for solving structured equation systems that are constructed from specific cryptosystems.
Dionysis Zindros
Surya Addanki, Kevin Garbe, Eli Jaffe, Rafail Ostrovsky, Antigoni Polychroniadou
Zhenzhen Bao, Jian Guo, Danping Shi, Yi Tu
Yuyin Yu, Leo Perrin
In this paper, we recall how to construct new QAMs from a known one, and present how used the ortho-derivative method to figure out which of our new functions fall into different CCZ-classes. Based on these results and on others on smaller fields, we make to conjectures: that the full list of quadratic APN functions on F28 could be obtained using the QAM approached (provided enormous computing power), and that the total number of CCZ-inequivalent APN functions may overcome 50000.
Elena Andreeva, Rishiraj Bhattacharyya, Arnab Roy
To enable efficiency analysis and comparison across hash functions built from primitives of different domain sizes, in this work we propose the new \textit{compactness} efficiency notion. It allows us to focus on asymptotically optimally collision resistant hash function and normalize their parameters based on Stam's bound from CRYPTO 2008 to obtain maximal efficiency.
We then present two tree-based modes of operation as a design principle for compact, large domain, fixed-input-length hash functions. \begin{enumerate} \item Our first construction is an \underline{A}ugmented \underline{B}inary T\underline{r}ee (\cmt) mode. The design is a $(2^{\ell}+2^{\ell-1} -1)n$-to-$n$-bit hash function making a total of $(2^{\ell}-1)$ calls to $2n$-to-$n$-bit compression functions for any $\ell\geq 2$. Our construction is optimally compact with asymptotically (optimal) $2^{n/2-\epsilon}$-query collision resistance in the ideal model. For a tree of height $\ell$, in comparison with Merkle tree, the $\cmt$ mode processes additional $(2^{\ell-1}-1)$ data blocks making the same number of internal compression function calls. \item With our second design we focus our attention on the indifferentiability security notion. While the $\cmt$ mode achieves collision resistance, it fails to achieve indifferentiability from a random oracle within $2^{n/3}$ queries. $\cmt^{+}$ compresses only $1$ less data block than $\cmt$ with the same number of compression calls and achieves in addition indifferentiability up to $2^{n/2-\epsilon}$ queries. \end{enumerate} Both of our designs are closely related to the ubiquitous Merkle Trees and have the potential for real-world applicability where the speed of hashing is of primary interest.