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27 April 2019
Abdelrahaman Aly, Tomer Ashur, Eli Ben-Sasson, Siemen Dhooghe, Alan Szepieniec
ePrint ReportFlavio Bergamaschi, Shai Halevi, Tzipora T. Halevi, Hamish Hunt
ePrint ReportWe adapt this method to train many models simultaneously using the SIMD capabilities of the CKKS scheme. We also performed a thorough validation of this iterative method and evaluated its suitability both as a generic method for computing logistic regression models, and specifically for GWAS.
Raghvendra Rohit
ePrint ReportIn particular, if $2n$ is the squeezing rate then the preimage security is approximately $(\text{log\textsubscript{2}}(\frac{3}{4}))^{-n} \times 2^{\frac{3n}{4}} \times (\text{log\textsubscript{2}}(3))^{\frac{n}{2}}$. For $n = 64$, 96 and 128, the former bound translates to $2^{125.28}$, $2^{187.92}$ and $2^{250.57}$, respectively.
Peter T. Breuer
ePrint ReportAlexander Moch, Eik List
ePrint ReportLiliya Akhmetzyanova, Evgeny Alekseev, Ekaterina Smyshlyaeva, Alexandr Sokolov
ePrint ReportIn this paper, we consider in detail the restriction on the usage of post-handshake authentication in connections established on external PSK. We clarify that the certain vulnerability appears only in the case of psk_ke mode if more than a single pair of entities can possess a single PSK. We provide several practical scenarios where this condition can be easily achieved. Also we propose appropriate mitigation.
Prasanna Ravi, Sourav Sen Gupta, Anupam Chattopadhyay, Shivam Bhasin
ePrint Report24 April 2019
Martin R. Albrecht, Carlos Cid, Lorenzo Grassi, Dmitry Khovratovich, Reinhard Lüftenegger, Christian Rechberger, Markus Schofnegger
ePrint ReportS. Sharmila Deva Selvi, Arinjita Paul, Siva Dirisala, Saswata Basu, C. Pandu Rangan
ePrint ReportJung Hee Cheon, Dongwoo Kim, Duhyeong Kim, Hun Hee Lee, Keewoo Lee
ePrint ReportIn this paper, we introduce iterative algorithms that approximately compute the min/max and comparison operations of several numbers which are encrypted word-wisely. From the concrete error analyses, we show that our min/max and comparison algorithms have $\Theta(\alpha)$ and $\Theta(\alpha\log\alpha)$ computational complexity to obtain approximate values within an error rate $2^{-\alpha}$, while the previous minimax polynomial approximation method requires the exponential complexity $\Theta(2^{\alpha/2})$ and $\Theta(\sqrt{\alpha}\cdot 2^{\alpha/2})$, respectively. We also show the (sub-)optimality of our min/max and comparison algorithms in terms of asymptotic computational complexity among polynomial evaluations to obtain approximate min/max and comparison results. Our comparison algorithm is extended to several applications such as computing the top-$k$ elements and counting numbers over the threshold in encrypted state.
Our new method enables word-wise HEs to enjoy comparable performance in practice with bit-wise HEs for comparison operations while showing much better performance on polynomial operations. Computing an approximate maximum value of any two $\ell$-bit integers encrypted by HEAAN, up to error $2^{\ell-10}$, takes only $1.14$ milliseconds in amortized running time, which is comparable to the result based on bit-wise HEs.
Evangelos Georgiadis
ePrint ReportRyuya Nakamura, Takayuki Jimba, Dominik Harz
ePrint Report23 April 2019
Xi'an, China, 15 November - 17 November 2019
Event CalendarSubmission deadline: 10 June 2019
Notification: 20 April 2019
TU Darmstadt
Job PostingCurrent topics of interest include (but are not limited to):
- Secure cryptographic implementations
- Leakage/tamper resilient cryptography
- Blockchains and cryptocurrencies
- Distributed cryptography
The application must include a curriculum vitae, a short research statement, and names of 2 contacts that can provide reference about the applicant and her/his work. The candidate shall be able to show solid expertise in cryptography/IT Security illustrated in form of publications at major crypto/security venues such as CRYPTO, EUROCRYPT, ASIACRYPT, TCC, PKC, CHES, FC, ACM CCS, IEEE S&P, USENIX Security, NDSS etc.
The position can be partially funded by the Ethereum Foundation and hence offers an internationally competitive salary including social benefits, and the opportunity for close collaboration with one of the leading cryptocurrencies.
TU Darmstadt offers excellent working environment and has a strong institute for research on IT security with more than 300 researchers working on all aspects of cybersecurity.
Review of applications starts immediately until the position is filled.
Closing date for applications: 14 June 2019
Contact: Prof. Sebastian Faust, Contact: sebastian.faust(at)cs(dot)tu-darmstadt(dot)de
The University of Sheffield, Department of Computer Science
Job PostingThe Department of Computer Science (https://www.sheffield.ac.uk/dcs) is embarking on an ambitious growth strategy following our strong performance in the Research Excellence Framework (REF) 2014, in which we were ranked 5th out of 89 computer science departments in the UK. The Department is part of the Faculty of Engineering, ranked 84th globally by the recent Times Higher Education (THE) World University Rankings, and holds a Silver Athena SWAN award, in recognition of our commitment to equality and diversity.
We are seeking candidates with an outstanding record of scholarship in cybersecurity. Suitable areas of expertise include (but are not limited to): security policies, threat modelling, authentication, access control, malware and malware detection, network security, secure protocols, secure software, security testing, and human factors and security. Candidates whose expertise includes elements of ‘security by design’ (primarily focused on software based systems) are particularly encouraged to apply.
You will hold a PhD in Computer Science or a relevant discipline (or have equivalent experience), and you will be able to conduct research to the highest standards. You will secure research funding, publish in high impact journals, supervise research students and manage research projects. As a teacher, you will play a key role in maintaining our reputation for high-quality teaching by designing, delivering and assessing undergraduate and postgraduate-level courses in cybersecurity and other core topics in computer science.
We’re one of the best not-for-profit organisations to work for in the UK. The University’s Total Reward Package includes a competitive salary, a generous Pension Scheme and annual leave entitlement, as well as access to a range of learning and development courses to support your personal and professional development.
Closing date for applications: 21 May 2019
Contact: Prof John Clark, Security of Advanced Systems Research Group Lead. An initial contact via email (john.clark (at) sheffield.ac.uk) is encouraged.
More information: https://www.jobs.ac.uk/job/BRR743/lecturer-senior-lecturer-in-cybersecurity
22 April 2019
Nico Dottling, Sanjam Garg, Mohammad Hajiabadi, Daniel Masny, Daniel Wichs
ePrint ReportItai Dinur
ePrint ReportThis problem was first considered by Jaeger and Tessaro (EUROCRYPT 2019), which proved that the adversary's advantage is upper bounded by $\sqrt{Q \cdot S/N}$. Jaeger and Tessaro used this bound as a streaming switching lemma which allowed proving that known time-memory tradeoff attacks on several modes of operation (such as counter-mode) are optimal up to a factor of $O(\log N)$ if $Q \cdot S \approx N$. However, if $Q \cdot S \ll N$ there is a gap between the upper bound of $\sqrt{Q \cdot S/N}$ and the $Q \cdot S/N$ advantage obtained by known attacks. Moreover, the bound's proof assumed an unproven combinatorial conjecture.
In this paper, we prove a tight upper bound (up to poly-logarithmic factors) of $O(\log Q \cdot Q \cdot S/N)$ on the adversary's advantage in the streaming distinguishing problem. The proof does not require a conjecture and is based on a reduction from communication complexity to streaming.