International Association for Cryptologic Research

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2013-11-07
07:17 [Pub][ePrint] Verifiable Set Operations over Outsourced Databases, by Ran Canetti and Omer Paneth and Dimitrios Papadopoulos and Nikos Triandopoulos

  We study the problem of verifiable delegation of computation over

outsourced data, whereby a powerful worker maintains a large data

structure for a weak client in a verifiable way. Compared to the

well-studied problem of verifiable computation, this setting imposes

additional difficulties since the verifier needs to verify consistency

of updates succinctly and without maintaining large state. In particular,existing general solutions are far from practical in this setting.

We present a scheme for verifiable evaluation of hierarchical set

operations (unions, intersections and set-differences) applied to a

collection of dynamically changing sets of elements from a given

domain. That is, we consider two types of queries issued by the

client: updates (insertions and deletions) and data queries, which

consist of ``circuits\'\' of unions, intersections, and set-differences

on the current collection of sets.

This type of queries comes up in database queries, keyword search and

numerous other applications, and indeed our scheme can be effectively

used in such scenarios. The verification cost incurred is proportional

only to the size of the final outcome set and to the size of the query, and is independent of the cardinalities of the involved sets. The cost of updates is optimal ($O(1)$ modular operations per update).

Our construction extends that of [Papamanthou et al., Crypto 2011]

and relies on a modified version of the \\emph{extractable collision-resistant hash function} (ECRH) construction, introduced in [Bitansky et al., ITCS 2012] that can be used to succinctly hash univariate polynomials.



07:17 [Pub][ePrint] Mobile Transaction over NFC and GSM, by Muhammad Qasim Saeed and Pardis Pourghomi

  Although NFC mobile services have great potential for growth, they have raised a number of issues which are of concern to researchers and are preventing the wide adoption of this technology within society. Dynamic relationships of NFC ecosystem players in an NFC transaction process make them partners in a way that sometimes requires that they share access permission to applications that are running in the service environment. One of the technologies that can be used to ensure secure NFC transactions is cloud computing. This offers a wider range of advantages than the use of a Secure Element (SE) as a single entity in an NFC enabled mobile phone. In this paper, we propose a protocol for NFC mobile payments based on cloud Wallet model. In our protocol, the SE in the mobile device is used for customer authentication whereas the customer\'s banking credentials are stored in a cloud under the control of the Mobile Network Operator (MNO). The proposed protocol eliminates the requirement for a shared secret between the Point of Sale (PoS) and the MNO before execution of the protocol, a mandatory requirement in the earlier version of this protocol. This makes it more practicable and user friendly. A detailed analysis of the protocol discusses multiple attack scenarios.



07:17 [Pub][ePrint] Homomorphic Authenticated Encryption Secure Against Chosen-Ciphertext Attack, by Chihong Joo and Aaram Yun

  We study homomorphic authenticated encryption, where privacy

and authenticity of data are protected simultaneously. We define homomorphic versions

of various security notions for privacy and authenticity, and investigate

relations between them. In particular, we show that it is possible to

give a natural definition of IND-CCA for homomorphic authenticated encryption, unlike

the case of homomorphic encryption. Also, we construct a homomorphic

authenticated encryption scheme supporting arithmetic circuits on $\\ZZ_Q$

for smooth modulus $Q$, which is chosen-ciphertext secure both for privacy

and authenticity. Our scheme is based on the error-free approximate GCD assumption.





2013-11-06
18:12 [Job][New] PhD studentships, Royal Holloway, University of London, UK

  We will be awarding 10 fully-funded studentships (generous stipend and college fees for four years) to outstanding candidates to join the Royal Holloway Centre for Doctoral Training in Cyber Security in October 2014.

We will consider applications from candidates with undergraduate and masters\\\' qualifications in a wide range of disciplines, including, but not limited to, mathematics, computer science, and electrical and electronic engineering.

Please see the Entry Requirements at http://www.rhul.ac.uk/isg/cybersecuritycdt/entryrequirements.aspx and instructions on How to Apply at http://www.rhul.ac.uk/isg/cybersecuritycdt/howtoapply.aspx. Funding is provided by the EPSRC, and thus is subject to their eligibility conditions. For further details, please visit the CDT Funding page at http://www.rhul.ac.uk/isg/cybersecuritycdt/funding.aspx.

Closing date for receiving applications is the 30th March 2014. We will however assess applications on an ongoing basis, and we reserve the right to make an offer to outstanding candidates before the closing date.

14:47 [Job][New] PhD student, SnT, University of Luxembourg, Luxembourg

  The Interdisciplinary Centre for Security, Reliability and Trust (SnT, www.securityandtrust.lu) at University of Luxembourg is looking for a PhD candidate in privacy-preserving recommender systems. The PhD topic is related to investigate the privacy issues in recommender systems and propose efficient and secure mechanisms to achieve the maximum privacy. The candidate is expected to design new privacy-preserving recommender systems for both horizontally and vertically partitioned dataset, prove their privacy properties, and study their asymptotical performances.

The student will work closely with the team members of the APSIA group, led by Prof. Peter Y. A. Ryan. Moreover, the student will be encouraged to collaborate with researchers from the group of Prof. Jiuyong Li at University of South Australia (UniSA), Australia.

For informal inquiries please contact: Dr. Qiang Tang qiang.tang (at) uni.lu

To formally apply for this position: http://emea3.mrted.ly/9lwj





2013-11-05
07:43 [Job][New] Professor (Open Rank), Worcester Polytechnic Institute, MA, USA, below Canada

  Worcester Polytechnic Institute (WPI) invites applications for a faculty position in the Department of Electrical & Computer Engineering at all ranks, commensurate with qualifications.

Required qualifications for the position include; an earned Ph.D. in Electrical & Computer Engineering, or a closely related field. Areas of particular interest include, but are not limited to: security engineering, hardware and embedded systems security, and mobile and cyber-physical systems security.

The successful candidate will be expected to establish and maintain a high quality, self-sustaining research program. WPI offers ample opportunity for collaboration with current department faculty as well as appropriate cross-campus, interdisciplinary research groups in various topics in security. In addition to excellence in teaching and research, candidates should look forward to engaging undergraduate and graduate students in a classroom and projects intensive environment, and expanding our graduate research program.

Qualified applicants should submit a detailed curriculum vitae, a brief statement of specific teaching and research objectives, and four letters of recommendation at least one of which addresses teaching experience or potential, via https://careers.wpi.edu/. Review of applications will begin on November 1, 2013 and will continue until the position is filled.



2013-11-04
13:39 [Event][New] Joint MPIM and B-IT workshop on Number Theory and Cryptography

  From November 20 to November 21
Location: Bonn, Germany
More Information: http://cosec.bit.uni-bonn.de/students/events/mpimbit/


13:00 [Event][New] ASIACCS 2014: 9th ACM Symposium on Information, Computer and Communications Security

  Submission: 6 December 2013
Notification: 27 January 2014
From June 4 to June 6
Location: Kyoto, Japan
More Information: http://www2.nict.go.jp/nsri/fund/asiaccs2014/index.html


13:00 [Event][New] RFIDSec'14: The 10th Workshop on RFID Security

  Submission: 1 March 2014
Notification: 15 April 2014
From July 21 to July 23
Location: Oxford, United Kingdom
More Information: http://www.sigsac.org/wisec/WiSec2014/


04:17 [Pub][ePrint] Outsourced Symmetric Private Information Retrieval, by Stanislaw Jarecki and Charanjit Jutla and Hugo Krawczyk and Marcel Rosu and Michael Steiner

  In the setting of searchable symmetric encryption (SSE), a data owner D outsources a database (or document/file collection) to a remote server E in encrypted form such that D can later search the collection at E while hiding information about the database and queries from E. Leakage to E is to be confined to well-defined forms of data-access and query patterns while preventing disclosure of explicit data and query plaintext values. Recently, Cash et al presented a protocol, OXT, which can run arbitrary Boolean queries in the SSE setting and which is remarkably efficient even for very large databases.

In this paper we investigate a richer setting in which the data owner

D outsources its data to a server E but D is now interested to allow clients (third parties) to search the database such that clients learn the information D authorizes them to learn but nothing else while E still does not learn about the data or queried values as in the basic SSE setting. Furthermore, motivated by a wide range of applications, we extend this model and requirements to a setting where, similarly to private information retrieval, the client\'s queried values need to be hidden also from the data owner D even though the latter still needs to authorize the query. Finally, we consider the scenario in which authorization can be enforced by the data owner D without D learning the policy, a setting that arises in court-issued search warrants.

We extend the OXT protocol of Cash et al to support arbitrary Boolean queries in all of the above models while withstanding adversarial

non-colluding servers (D and E) and arbitrarily malicious clients,

and while preserving the remarkable performance of the protocol.





2013-11-03
22:17 [Pub][ePrint] A Secure Obfuscator for Encrypted Blind Signature Functionality, by Xiao Feng and Zheng Yuan

  This paper introduces a new obfuscation called obfuscation of encrypted blind signature. Informally, encrypted blind signature enable the message is blind to signer, and she couldn\'t distinguish two encrypted signatures by herself. A obfuscation of encrypted blind signature makes the process of encrypted blind signature unintelligible for any third party, while still keeps the original encrypted blind signature functionality. We use schnorr\'s blind signature scheme and linear encryption scheme as blocks to construct a new obfuscator. Moreover, we propose two new security definition: blindness w.r.t encrypted blind signature (EBS) obfuscator and one-more unforgeability(OMU) w.r.t EBS obfuscator, and prove them based on Decision Liner Diffie-Hellman(DL) assumption and the hardness of discrete logarithm, respectively. We also demonstrate that our obfuscator satisfies the Average-Case Virtual Black-Box Property(ACVBP) property w.r.t dependent oracle, it is indistinguishable secure. Our paper expand a new direction for the application of obfuscation.