IACR News
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13 May 2016
Masahiro Yagisawa
Daniel J. Bernstein, Chitchanok Chuengsatiansup, Tanja Lange, Christine van Vredendaal
This paper proposes NTRU Prime, which tweaks NTRU to use rings without these structures; proposes Streamlined NTRU Prime, which optimizes NTRU Prime from an implementation perspective; finds high-security post-quantum parameters for Streamlined NTRU Prime; and optimizes a constant-time implementation of those parameters. The performance results are surprisingly competitive with the best previous speeds for lattice-based cryptography.
Kwangsu Lee, Seunghwan Park
In this paper, we propose efficient RHIBE schemes with shorter private keys and update keys and small public parameters by removing this multiplicative factor. To achieve our goals, we first present a new HIBE scheme with the different generation of private keys such that a private key can be simply derived from a short intermediate private key. Next, we show that two efficient RHIBE schemes can be built by combining our HIBE scheme, an IBE scheme, and a tree based broadcast encryption scheme in a modular way.
Zvika Brakerski, Justin Holmgren, Yael Kalai
Previous works either relied on knowledge assumptions, or could only offer non-adaptive two-message protocols (where the first message could not be re-used), and required either obfuscation-based assumptions or super-polynomial hardness assumptions.
We show that our techniques can also be applied to construct a new type of (non-adaptive) 2-message delegation protocols for batch NP statements. Specifically, we can simultaneously prove the membership of multiple instances in a given NP language, with communication complexity proportional to the length of a single witness.
Adam Groce, Alex Ledger, Alex J. Malozemoff, Arkady Yerukhimovich
Improving on the above technique, we give a second method of chaining, which we call single communication multiple connections chaining, which allows blocks of consecutive wires holding multi-bit pieces of data to be connected between components with only a single transmitted wire label. This means that connecting components requires minimal communication.
Finally, we give an implementation, CompGC, of these techniques and measure the efficiency gains for various examples. We find that our techniques result in roughly an order of magnitude performance improvement over standard garbled circuit-based secure two-party computation.
Wei Yuan
Yuval Ishai, Eyal Kushilevitz, Manoj Prabhakaran, Amit Sahai, Ching-Hua Yu
Simplifying feasibility results: Easily rederive a result in Goldreichs book (2004), on MPC with full security in the presence of an honest majority, from an earlier result in the book, on MPC that offers security with abort. Rederive the classical result of Rabin and Ben-Or (1989) by applying a transformation to the simpler protocols of Ben-Or et al. or Chaum et al. (1988). Efficiency improvements: The first constant-rate MPC protocol for a constant number of parties that offers full information-theoretic security with an optimal threshold, improving over the protocol of Rabin and Ben-Or; A fully secure MPC protocol with optimal threshold that improves over a previous protocol of Ben-Sasson et al. (2012) in the case of deep and narrow computations; A fully secure MPC protocol with near-optimal threshold that improves over a previous protocol of Damgård et al. (2010) by improving the dependence on the security parameter from linear to polylogarithmic; An efficient new transformation from passive-secure two-party computation in the OT-hybrid and OLE-hybrid model to zero-knowledge proofs, improving over a recent similar transformation of Hazay and Venkitasubramaniam (2016).
Finally, we prove the impossibility of two simple types of black-box protocol transformations, including an unconditional variant of a previous negative result of Rosulek (2012) that relied on the existence of one-way functions.
Linus Feiten, Matthias Sauer
11 May 2016
Bletchley, UK, 15 June 2016
Kaiserslautern, Germany, 29 August - 2 September 2016
University of Surrey
Job Titles:
Closing date for applications: 13 June 2016
Contact: Helen Treharne, Reader in Secure Systems
More information: https://jobs.surrey.ac.uk/Vacancies.aspx
Monash University, Australia
Your research expertise in one of the following research areas is pivotal to the success of this role:
- security of advanced networking infrastructures (VNF, SDN, etc.)
- cross-layer security (from physical layer up to applications, including meta-data)
- secure roots of trust and trust management for IoT, critical infrastructures, virtualization
- interdisciplinary cyber security
- resilience of IT-based infrastructures
- IoT with cyber security focus (automation, robotics, sensors/actuators, etc.)
- software security
- mobile security, Android, iOS
- forensics, cyber-crime, forensic readiness.
If you have an excellent record of scholarly, high quality, high impact publications in refereed journals and conferences in areas of cyber security, we urge you to apply.
IMPORTANT: It is essential for your application to include a letter answering your suitability according to the key selection criteria (Please refer to \"How to apply for Monash Jobs\"). In addition, it would be helpful if your CV contains, for each high quality, high impact publication, a brief indication of its impact (in terms of citations) and of the quality of the venue. For the latter, please refer to the CORE conference and journal rankings www.core.edu.au/index.php
For the former, please refer to Google Scholar, Scopus, or Thomson Reuters.
This role is a full-time or part-time position; flexible working arrangements can be negotiated.
Closing date for applications: 29 May 2016
Contact: Associate Professor Carsten Rudolph
More information: http://www.jobs-monash.jxt.net.au/academic-jobs/lecturer-senior-lecturer-cyber-secruity/625850
10 May 2016
Grace team, INRIA Saclay et Ecole polytechnique, Palaiseau, Paris greater area, France
INRIA is participating in the European H2020 PQCRYPTO project, http://pqcrypto.eu.org , whose aim is to recommend cryptographic primitives still secure after the potential advent of the quantum computer.
INRIA team Grace is involved in the topic\"advanced applications\", like searchable encryption, homomorphic encryption, secure multi-party computation, and has to deliver recommendations.
Besides the EU project PQCRYPTO, Grace wants to invest and put efforts in the topic of information theoretically secure multi-party computation (MPC).
Also, Grace would like to investigate how multi-party computation is useful in the context of blockchains.
Mission
The mission is to support project-team Grace in his growing involvement in (information theoretically) secure multi-party computation.
While the team masters mathematical and algorithmic aspects underlying secret sharing schemes relevant to information theoretically secure MPC (coding theory, algebraic function fields over finite fields), the team\'s knowledge of the MPC security models (simulation, universal composition) needs to be strenghtened. In particular, it is not clear how a powerful quantum adversary may affect these models.
The second part of the mission would be to help distinguishing between general purpose MPC and decidated MPC, for main applications.
The position may be extended for a second year.
Job description
Within H2020 PQCRYPTO, the applicant will be in charge, with the team leader and European researchers, of delivering the final recommendations. He will help the project participants to elaborate a plan and guidelines for these recommendations. He will also interfere with specialists in quantum computing, to assess the security models of MPC schemes in presence of a quantum adversary.
Profile
The candidate should have the done a PhD thesis in the topic of MPC computation, and know well the security models underlying the topic, with all their subtleties.
Closing date for applications: 31 May 2016
Contact: Daniel Augot
batiment Alan Turing
1 rue d\'Estienne d\'Orves
campus de l\'Ecole polytechnique
Palaiseau
France
More information: http://bit.ly/24HTRc6
Ä°zmir, Turkey, 1 September - 7 September 2016
Hanoi, Vietnam, 27 November - 4 December 2016
Cannes, France, 7 November - 9 November 2016
Submission deadline: 15 July 2016
Notification: 8 September 2016
Seoul, Korea, 30 November - 2 December 2016
Submission deadline: 26 August 2016
Notification: 21 October 2016
Rafael Pass, Lior Seeman, abhi shelat
The analysis of the blockchain consensus protocol (a.k.a. Nakamoto consensus) has been a notoriously difficult task. Prior works that analyze it either make the simplifying assumption that network channels are fully synchronous (i.e. messages are instantly delivered without delays) (Garay et al, Eurocrypt'15) or only consider specific attacks (Nakamoto'08; Sampolinsky and Zohar, FinancialCrypt'15); additionally, as far as we know, none of them deal with players joining or leaving the protocol.
In this work we prove that the blockchain consensus mechanism satisfies a strong forms of *consistency* and *liveness* in an asynchronous network with adversarial delays that are a-priori bounded, within a formal model allowing for adaptive corruption and spawning of new players, assuming that the computational puzzle is modeled as a random oracle. (We complement this result by showing a simple attack against the blockchain protocol in a fully asynchronous setting, showing that the puzzle-hardness needs to be appropriately set as a function of the maximum network delay; this attack applies even for static corruption.)
As an independent contribution, we define an abstract notion of a blockchain protocol and identify appropriate security properties of such protocols; we prove that Nakamoto's blockchain protocol satisfies them and that these properties are sufficient for typical applications; we hope that this abstraction may simplify further applications of blockchains.
Seny Kamara, Tarik Moataz
Benjamin Dowling, Felix Günther, Udyani Herath, Douglas Stebila
In this work, we define four security properties of logging schemes such as CT that can be assured via cryptographic means, and show that CT does achieve these security properties. We consider two classes of security goals: those involving security against a malicious logger attempting to present different views of the log to different parties or at different points in time, and those involving security against malicious monitors who attempt to frame an honest log for failing to include a certificate in the log. We show that Certificate Transparency satisfies these security properties under various assumptions on Merkle trees all of which reduce to collision resistance of the underlying hash function (and in one case with the additional assumption of unforgeable signatures).