International Association for Cryptologic Research

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2015-02-14
10:17 [Pub][ePrint] Structural Weaknesses in the Open Smart Grid Protocol, by Klaus Kursawe and Christiane Peters

  The Open Smart Grid Protocol (OSGP) is currently deployed in various European countries in large-scale Smart Metering projects. The protocol was developed by the OSGP Alliance and published as a standard by the European Telecommunications Standards Institute (ETSI).

We identify several security issues in the OSG Protocol, primarily the use of a weak digest function and the way the protocol utilizes the RC4 algorithm for encryption. A straight-forward oracle attack triggers the leakage of key material of the digest function. We outline how an attacker can make use of the simple protocol structure to send maliciously altered messages with valid authentication tags to the meters.

The results of our analysis have been made available to the manufacturer the beginning of 2014, and mitigation strategies have been discussed with the vendor and utilities.





2015-02-12
13:13 [Job][New] Research scientist & post-doc, Advanced Digital Sciences Center, Singapore

  We are actively seeking competent researchers for the project \"A Cyber-Physical Approach to Securing Urban Transportation Systems\" - Future cities will increasingly be smart, providing an environment where people\'s everyday lives are supported by various cyber-physical infrastructures including urban transportation systems. ADSC will develop new security technologies for urban transportation systems and make fundamental breakthroughs in cyber security research through collaboration with Singapore\'s Institute for Infocomm Research (I2R), Singapore University of Technology and Design (SUTD), and industry partners.

13:10 [Job][New] Post-doctorate in Information and Network Security, The Information Security Centre of Excellence, University of New Brunswick, Fredericton, Canada

  The Information Security Centre of Excellence (ISCX) is seeking a full-time postdoctoral fellow to work with Dr. Natalia Stakhanova to carry out research & development activities in the areas of Critical infrastructure protection and Network Security. The Center is a vibrant research centre known for its active collaboration with industry.

Applicants should have an expertise in one or more of the following research areas:

• Network Security, and network technologies and tools.

• Security of Critical infrastructure

• Malware analysis

The post-doc appointment is for one year and can be extended for up to three more years depending upon the availability of funding.

Applications will be considered until the available position is filled. To apply submit your CV via email to Dr. Natalia Stakhanova

natalia(dot)stakhanova(at)unb.ca



03:30 [Job][New] PostDoc on Vehicular Networking Security, Institute of Distributed Systems, Ulm University, Germany

  You are expected to support and strengthen our research activities in the area of security and privacy in Intelligent Transport Systems (ITS) and vehicular networking. In addition, you may contribute to topics like high-speed networking and physical-layer security. You will work in ongoing projects, as well as contribute to new project proposals. You will be involved in project management and support the supervision of PhD candidates.

The ideal candidate has experience in ITS security or vehicular networking, which is docu­mented by high-quality publications, a Ph.D. degree in computer science or a closely related discipline from an internationally renowned university, and a strong motivation to become part of our team. Proficient knowledge of written and spoken English is required. Conversational German skills are an advantage.



2015-02-11
14:30 [Event][New] ICISS 2015: 11th International Conference on Information Systems Security

  Submission: 29 July 2015
Notification: 15 September 2015
From December 16 to December 20
Location: Kolkata, India
More Information: http://www.iciss.org.in


07:17 [Pub][ePrint] On the Difficulty of Securing Web Applications using CryptDB, by İhsan Haluk AKIN and Berk Sunar

  CryptDB has been proposed as a practical and secure

middleware to protect databases deployed on semi-honest

cloud servers. While CryptDB provides sufficient protection

under Threat-1, here we demonstrate that when CryptDB is

deployed to secure the cloud hosted database of a realistic web

application, an attacker to database or a Malicious Database

Administrator (mDBA) can easily steal information, and even

escalate his privilege to become the administrator of the

web application. Our attacks, fall under a restricted form

of Threat-2 where we only assume that the attackers or the

mDBA tampers with the CryptDB protected database and is

opens an ordinary user account through the web application.

Our attacks, are carried out assuming perfectly secure proxy

and application servers. Therefore, the attacks work without

recovering the master key residing on the proxy server. At

the root of the attack lies the lack of any integrity checks

for the data in the CryptDB database. We propose a number

of practical countermeasures to mitigate attacks targeting the

integrity of the CryptDB database. We also demonstrate that

the data integrity is not sufficient to protect the databases,

when query integrity and frequency attacks are considered.



02:59 [Event][New] ECTCM 2015: Third International Workshop on Emerging Cyberthreats and Countermeasures

  Submission: 31 March 2015
From August 24 to August 28
Location: Toulouse, France
More Information: http://www.ectcm.net


01:17 [Pub][ePrint] Amortizing Garbled Circuits, by Yan Huang and Jonathan Katz and Vladimir Kolesnikov and Ranjit Kumaresan and Alex J. Malozemoff

  We consider secure two-party computation in a multiple-execution setting, where two parties wish to securely evaluate the same circuit multiple times. We design efficient garbled-circuit-based two-party protocols secure against malicious adversaries. Recent works by Lindell (Crypto 2013) and Huang-Katz-Evans (Crypto 2013) have obtained optimal complexity for cut-and-choose performed over garbled circuits in the single execution setting. We show that it is possible to obtain much lower amortized overhead for cut-and-choose in the multiple-execution setting.

Our efficiency improvements result from a novel way to combine a recent technique of Lindell (Crypto 2013) with LEGO-based cut-and-choose techniques (TCC 2009, Eurocrypt 2013). In concrete terms, for 40-bit statistical security we obtain a 2x improvement (per execution) in communication and computation for as few as 7 executions, and require only 8 garbled circuits (i.e., a 5x improvement) per execution for as low as 3500 executions. Our results suggest the exciting possibility that secure two-party computation in the malicious setting can be less than an order of magnitude more expensive than in the semi-honest setting.





2015-02-10
22:17 [Pub][ePrint] Mind the Gap: Modular Machine-checked Proofs of One-Round Key Exchange Protocols, by Gilles Barthe and Juan Manuel Crespo and Yassine Lakhnech and Benedikt Schmidt

  Using EasyCrypt, we formalize a new modular security proof for one-round authenticated key exchange protocols in the random oracle model. Our proof improves earlier work by Kudla and Paterson (ASIACRYPT 2005) in three significant ways: we consider a stronger adversary model, we provide support tailored to protocols that utilize the Naxos trick, and we support proofs under the Computational DH assumption not relying on Gap oracles. Furthermore, our modular proof can be used to obtain concrete security proofs for protocols with or without adversarial key registration. We use this support to investigate, still using EasyCrypt, the connection between proofs without Gap assumptions and adversarial key registration. For the case of honestly generated keys, we obtain the first proofs of the Naxos and Nets protocols under the Computational DH assumption. For the case of adversarial key registration, we obtain machine-checked and modular variants of the well-known proofs for Naxos, Nets, and Naxos+.



22:17 [Pub][ePrint] Equivalent Key Recovery Attacks against HMAC and NMAC with Whirlpool Reduced to 7 Rounds, by Jian Guo and Yu Sasaki and Lei Wang and Meiqin Wang and Long Wen

  A main contribution of this paper is an improved analysis against HMAC instantiating with reduced Whirlpool. It recovers equivalent keys, which are often denoted as Kin and Kout, of HMAC with 7-round Whirlpool, while the previous best attack can work only for 6 rounds. Our approach is applying the meet-in-the-middle (MITM) attack on AES to recover MAC keys of Whirlpool. Several techniques are proposed to bypass different attack scenarios between a block cipher and a MAC, e.g., the chosen plaintext model of the MITM attacks on AES cannot be used for HMAC-Whirlpool. Besides, a larger state size and different key schedule designs of Whirlpool leave us a lot of room to study. As a result, equivalent keys of HMAC with 7-round Whirlpool are recovered with a complexity of (Data, Time, Memory) = (2^481.7, 2^482.3, 2^481).



22:17 [Pub][ePrint] Fully Structure-Preserving Signatures and Shrinking Commitments, by Masayuki Abe and Markulf Kohlweiss and Miyako Ohkubo and Mehdi Tibouchi

  Structure-preserving signatures are schemes in which

public keys, messages, and signatures are all collections of source group elements of

some bilinear groups. In this paper, we introduce fully structure-preserving signature

schemes, with the additional requirement that even secret keys should be group elements.

This new type of structure-preserving signatures allows for

efficient non-interactive proofs of knowledge of the secret key and is

useful in designing cryptographic protocols with strong security guarantees

based on the simulation paradigm where the simulator has to extract the

secret keys on-line.

To gain efficiency, we construct shrinking structure-preserving trapdoor

commitments. This is by itself an important primitive and of independent

interest as it appears to contradict a known impossibility result. We argue that a relaxed binding

property lets us circumvent the impossibility result while still retaining the

usefulness of the primitive in important applications as mentioned above.