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11 April 2018
Zvika Brakerski
We present a QFHE scheme with classical key generation (and classical encryption and decryption if the encrypted message is itself classical) with comparable properties to classical FHE. Security relies on the hardness of the learning with errors (LWE) problem with polynomial modulus, which translates to the worst case hardness of approximating short vector problems in lattices to within a polynomial factor. Up to polynomial factors, this matches the best known assumption for classical FHE. Similarly to the classical setting, relying on LWE alone only implies leveled QFHE (where the public key length depends linearly on the maximal allowed evaluation depth). An additional circular security assumption is required to support completely unbounded depth. Interestingly, our circular security assumption is the same assumption that is made to achieve unbounded depth multi-key classical FHE.
Technically, we rely on the outline of Mahadev (arXiv 2017) which achieves this functionality by relying on super-polynomial LWE modulus and on a new circular security assumption. We observe a connection between the functionality of evaluating quantum gates and the circuit privacy property of classical homomorphic encryption. While this connection is not sufficient to imply QFHE by itself, it leads us to a path that ultimately allows using classical FHE schemes with polynomial modulus towards constructing QFHE with the same modulus.
Marc Fischlin, Patrick Harasser
David Urbanik, David Jao
Nir Drucker, Shay Gueron
Dong Yang, Wen-feng Qi, Hua-jin Chen
Tianren Liu, Vinod Vaikuntanathan
There is a large gap between lower and upper bounds for secret sharing. The best known scheme for general $\mathsf F$ has shares of size $2^{n-o(n)}$, but the best lower bound is $\Omega(n^2/\log n)$. Indeed, the exponential share size is a direct result of the fact that in all known secret-sharing schemes, the share size grows with the size of a circuit (or formula, or monotone span program) for $\mathsf F$. Indeed, several researchers have suggested the existence of a {\em representation size barrier} which implies that the right answer is closer to the upper bound, namely, $2^{n-o(n)}$.
In this work, we overcome this barrier by constructing a secret sharing scheme for any access structure with shares of size $2^{0.994n}$ and a linear secret sharing scheme for any access structure with shares of size $2^{0.999n}$. As a contribution of independent interest, we also construct a secret sharing scheme with shares of size $2^{\tilde{O}(\sqrt{n})}$ for $2^{{n\choose n/2}}$ monotone access structures, out of a total of $2^{{n\choose n/2}\cdot (1+O(\log n/n))}$ of them. Our construction builds on recent works that construct better protocols for the conditional disclosure of secrets (CDS) problem.
CEA Leti
Summary : Secure chip manufacturers must ensure the protection of the confidential information contained in their component. This involves software countermeasures (data encryption by a crypto-processor) as well as hardware protections since attackers are now able to access information by attacking the chip with physical methods. Unlike the active side which already includes countermeasures, the back side of the chips remains a preferred target because it is more vulnerable and closer to the active layers of the circuit.
CEA-Leti is working on the development of an efficient, low cost and low power protection using technologies derived from 3D integration. An innovative backside shield, designed and patented by the Leti / DCOS packaging laboratory, was fabricated and showed its effectiveness against fault injection and other typical attacks. Some improvements in the design and structure of the shield have been identified to make it even more difficult to attack. Finally, an extension of the concept to a whole system has been considered in order to collectively protect the back side of several chips.
As part of this thesis, the improvement of the structure and its extension to a system will be studied, in order to propose an optimized design and to lead the technological developments necessary to its implementation on a demonstrator. The PhD student will conduct thermo-mechanical simulation work to size the protection elements for optimal efficiency, then he will participate in the design of the masks necessary for their realization. He will follow the process developments in the clean room and will take part in the physical and / or electrical characterizations. Throughout these processes, he will interact with Leti\'s security experts to ensure that the developments are consistent with the state of the art in terms of attacks and countermeasures.
Closing date for applications: 31 May 2018
Contact: Dr Stefan Borel
stephan.borel (at) cea.fr
CEA Leti
- \"On the use of wavelets for side-channel analysis\"
French : http://www-instn.cea.fr/formations/formation-par-la-recherche/doctorat/liste-des-sujets-de-these/ondelettes-pour-le-traitement-des-signaux-compromettants,18-0769.html
English : http://www-instn.cea.fr/en/education-and-training/research-training/phd-programs/list-of-thesis-subjects/wavelets-applied-to-side-channel-analysis,18-0769/pdf.html
- \"Integrated circuit modification with focalized X-Ray beams and a FIB\"
French : http://www-instn.cea.fr/formations/formation-par-la-recherche/doctorat/liste-des-sujets-de-these/modification-de-circuits-electroniques-avec-lutilisation-de-rayons-x-et-dun-fib,18-0633.html
English : http://www-instn.cea.fr/en/education-and-training/research-training/phd-programs/list-of-thesis-subjects/integrated-circuit-modification-with-focalized-xrays-beam-and-fib,18-0633/pdf.html
- \"Symbolic execution methods on binary codes to detect perturbations attacks vulnerabilities\"
French : http://www-instn.cea.fr/formations/formation-par-la-recherche/doctorat/liste-des-sujets-de-these/methodes-d-execution-symbolique-de-code-binaire-pour-detections-de-vulnerabilites-contre-les,18-0767.html
English : http://www-instn.cea.fr/en/education-and-training/research-training/phd-programs/list-of-thesis-subjects/symbolic-execution-methods-on-binary-codes-to-detect-perturbations-attacks-vulnerabilities,18-0767/pdf.html
- \"Secure implementation of stream ciphers\"
French : http://www-instn.cea.fr/formations/formation-par-la-recherche/doctorat/liste-des-sujets-de-these/securisation-de-l-implementation-des-mecanismes-de-chiffrements-par-flot,18-0762.html
English : http://www-instn.cea.fr/en/education-and-training/research-training/phd-programs/list-of-thesis-subjects/secure-implementation-of-stream-ciphers,18-0762/pdf.html
Closing date for applications: 31 May 2018
Contact: Jacques Fournier, PhD, HDR
Senior Scientist
jacques.fournier (at) cea.fr
University of Luxembourg
The position is within the national project PrivDA, whose goal is to develop models and techniques for privacy-preserving data publication from dynamic social networks, accounting for the presence of active adversaries (adversaries with the ability to alter the network structure).
We welcome applications from candidates who have completed a Ph. D. degree in Computer Science or Mathematics by May 2018.
Preference will be given to applicants with proven interest in graph theory and/or data privacy and/or social network analysis.
The intended start day is June 1st, 2018.
The University offers a two-year employment contract, which may be extended up to five years.
Closing date for applications: 30 April 2018
Contact: Yunior Ramirez-Cruz, e-mail: yunior.ramirez (at) uni.lu
Sjouke Mauw, e-mail: sjouke.mauw (at) uni.lu
More information: http://emea3.mrted.ly/1rxbi
University of Oslo
The successful candidate for this PhD fellowship position will contribute to a flexible security framework, which assists developers in creating secure services, but also supports automatic service-usage in machine-to-machine communication.
One focus of this PhD project might be: lightweight security mechanisms, security specification languages, security negotiation protocols, code generation for secure communication stubs etc.
Closing date for applications: 15 April 2018
Contact: Nils Gruschka, +47 22840858, nils.gruschka (at) ifi.uio.no
More information: https://www.jobbnorge.no/en/available-jobs/job/149459/phd-research-fellowship-in-cybersecurity
University of Waterloo, Institute for Quantum Computing
Qualifications:
• Undergraduate or Graduate degree in Mathematics, Computer Science or Electrical and Computer Engineering
• Essential: C and C++ programming experience, at least 3 years.
• Essential: Familiarity with cryptographic algorithms including public key and symmetric key cryptography, digital signatures, message digest and hashing algorithms
• Essential: Familiarity with version control systems (Git & Github workflow)
The Institute for Quantum Computing (IQC) is a world-leading institute for research in quantum information at the University of Waterloo.
The appointment will be for 12 months with the possibility of extension, pending on research funding. The salary is competitive and commensurate with experience. The University of Waterloo respects, appreciates and encourages diversity. All qualified candidates are encouraged to apply; however, Canadian citizens and permanent residents will be given priority
Closing date for applications: 24 August 2018
Contact: Michele Mosca
michele.mosca (at) uwaterloo.ca
More information: https://services.iqc.uwaterloo.ca/applications/positions/open-quantum-safe-liboqs-cryptographi-x9y4/
10 April 2018
Ralph Ankele, Eik List
In this paper, we present chosen-ciphertext differential attacks on 16 rounds of Sparx-64/128. First, we show a truncated-differential analysis that requires $2^{32}$ chosen ciphertexts and approximately $2^{93}$ encryptions. Second, we illustrate the effectiveness of boomerangs on Sparx by a rectangle attack that requires approximately $2^{59.6}$ chosen ciphertexts and about $2^{122.2}$ encryption equivalents. Finally, we also considered a yoyo attack on 16 rounds that, however, requires the full codebook and approximately $2^{126}$ encryption equivalents.
09 April 2018
Martin R. Albrecht, Benjamin R. Curtis, Amit Deo, Alex Davidson, Rachel Player, Eamonn W. Postlethwaite, Fernando Virdia, Thomas Wunderer
Joseph K. Liu, Tsz Hon Yuen, Peng Zhang, Kaitai Liang
Pasquale Malacaria , MHR. Khouzani, Corina S. P\u{a}s\u{a}reanu, Quoc-Sang Phan, Kasper Luckow
Turku, Finland, 28 May - 1 June 2018
Submission deadline: 1 May 2018
Notification: 8 May 2018