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2013-02-01
12:59 [Job][New] Post-Doc in security in virtualized software systems, The Security Lab at Swedish Institute of Computer Science (SICS), Sweden

  The Security Lab at Swedish Institute of Computer Science (SICS) in Stockholm is looking for a talent post doc researcher candidate in the area of security for virtualized software systems. The position is for one year and should be done through the ERCIM Alain Bensoussan Fellowship Programme with deadline February 28. We are looking for a talent researcher with interest in applied research and good knowledge in Trusted Computing Technologies.

The security Lab at SICS was established in 2009. Since then it has grown from 1 to 8 people. The research is directed toward secure systems design in close co-operation with above leading Swedish companies in the IT and telecommunications businesses as well as Swedish universities such as Royal Institute of Technology in Stockholm. The group has developed an own hypervisor providing secure execution in ARM based embedded systems that currently undergo formal verification. Furthermore, the group is performing lots of research on usage of Trusted Computing technologies to secure future cloud infrastructures. The secure systems group at SICS consists for the moment of 4 senior researchers (PhD), 2 PhD students and addition 2 junior researchers with MSc degrees in computer science.



04:17 [Pub][ePrint] Power Balanced Circuits for Leakage-Power-Attacks Resilient Design, by Basel Halak, Julian Murphy, Alex Yakovlev

  The continuous rise of static power consumption in

modern CMOS technologies has led to the creation of a novel

class of security attacks on cryptographic systems. The latter

exploits the correlation between leakage current and the input

patterns to infer the secret key; it is called leakage power analysis

(LPA). The use power-balanced (m-of-n) logic is a promising

solution that provides an answer to this problem, such circuits

are designed to consume constant amount of power regardless of

data being processed. This work evaluates the security of

cryptographic circuits designed with this technology against the

newly developed LPA. Two forms of LPA are investigated, one is

based on differential power analysis (LDPA) and the other based

on Hamming weight analysis (LHPA). Simulations performed at

90nm CMOS technology reveal that (m-of-n) circuits are totally

resilient to LHPA and have a higher security level against LDPA

than standard logic circuits.



04:17 [Pub][ePrint] Lessons Learned From Previous SSL/TLS Attacks - A Brief Chronology Of Attacks And Weaknesses, by Christopher Meyer and Jörg Schwenk

  Since its introduction in 1994 the Secure Socket Layer (SSL) protocol (later renamed to Transport Layer Security (TLS)) evolved to the de facto standard for securing the transport layer. SSL/TLS can be used for ensuring data confidentiality, integrity and authenticity during transport. A main feature of the protocol is its flexibility. Modes of operation and security aims can easily be configured through different cipher suites. During its evolutionary development process several flaws were found. However, the flexible architecture of SSL/TLS allowed efficient fixes in order to counter the issues. This paper presents an overview on theoretical and practical attacks of the last 15 years, in chronological order and four categories: Attacks on the TLS Handshake protocol, on the TLS Record and Application Data Protocols, on the PKI

infrastructure of TLS, and on various other attacks. We try to give a short \"Lessons Learned\" at the end of each paragraph.





2013-01-30
19:17 [Pub][ePrint] Lower Bounds on the Information Ratio of Linear Secret Sharing Schemes, by Carles Padro

  Superpolynomial lower bounds on the average information ratio of linear secret sharing scheme are presented in this note for the first time. The previously known superpolynomial lower bounds applied only to the average information ratio of linear schemes in which the secret is a single field element. The new bounds are obtained by a simple adaptation of the techniques in those previous works.



04:17 [Pub][ePrint] Efficient Computation Outsourcing for Inverting a Class of Homomorphic Functions, by Fangguo Zhang and Xu Ma and Shengli Liu

  The rise of cloud computing and the proliferation of mobile devices make computation outsourcing popular. However, the servers are not fully trusted, and a critical problem is the verifiability and privacy of such computations. Although some computation outsoucing schemes provided a general method, the complicated cryptographic tools involved result in great inefficiency. The existing efficient computation outsourcing schemes however aim only at a specific computation task, lacking in generality. In this paper, we show how to construct a generic outsourcing computation scheme for inverting a class of homomorphic functions with computation disequilibrium. Extensive analysis shows that many cryptographic computations fall into this category. The formal security analysis proves that our scheme satisfies verifiability, input and output privacy in information-theoretic sense. Since the construction of our scheme tactfully takes advantage of the intrinsic property of the computation task being outsourced, no public key operations are used in the scheme, thus our solution clearly outperforms the existing schemes in terms of efficiency. In addition, we instantiate our generic construction with concrete examples, and the experimental result testifies the efficiency of our construction.



04:17 [Pub][ePrint] Towards Efficient Verifiable SQL Query for Outsourced Dynamic Databases in Cloud, by anonymized for paper review

  With the raising trend of outsourcing databases to the cloud server, it is important to efficiently and securely assure that the clients\' queries on the databases are executed correctly. To address this issue, server schemes have been proposed based on various cryptographic tools. However, these existing schemes have limitations in either communication cost or computational cost for verification. Meanwhile, only four types of SQL functional queries are supported in these schemes. It still remains as an open problem to design a verifiable SQL query scheme that provides affordable storage overhead, communication cost, computational cost and more SQL functional queries.

In this paper, we investigate this open problem and propose an efficient verifiable SQL query scheme for outsourced dynamic databases. Different from the previous state-of-the-art schemes, we reduce the complexity of storage overhead from O(mn) to O(n) and move most computation tasks from client side to cloud server side. Compared with the recently proposed scheme that also achieves O(n) storage overhead, we not only cut the communication complexity for verification from O(n) to O(log^n), but also release the client from O(n) exponentiation operations to O(1). In addition, our proposed scheme improves the previous ones by allowing more aggregate queries including variance query, weighted exponentiation sum query of any degrees, etc. Thorough analysis shows the efficiency and scalability of our proposed scheme. The security of our scheme is proved based on Strong Diffie-Hellman Assumption, Bilinear Strong Diffie-Hellman Assumption and Computational Diffie-Hellman Assumption.



04:17 [Pub][ePrint] Fast and Maliciously Secure Two-Party Computation Using the GPU, by Tore Kasper Frederiksen and Jesper Buus Nielsen

  We describe, and implement, a maliciously secure protocol for secure two-party computation, based on Yao\'s garbled circuit and an efficient OT extension, in a parallel computational model. The implementation is done using CUDA and yields the fastest results for maliciously secure two-party computation in a realistic and practical setting by using a simple consumer grade CPU and GPU. Our protocol further introduces some novel constructions in order to combine garbled circuits and an OT extension in a parallel and maliciously secure setting.



01:17 [Pub][ePrint] EMV Key Agreement, by Christina Brzuska and Nigel P. Smart and Bogdan Warinschi and Gaven J. Watson

  We present an analysis of the recently proposed key agreement protocol for use by EMV cards (a.k.a. chip-and-pin cards).



01:17 [Pub][ePrint] Detection of Cheaters in Non-interactive Polynomial Evaluation, by Maki Yoshida and Satoshi Obana

  In this paper, we consider both theoretical and practical aspects of

robust NI-PE (non-interactive polynomial evaluation with detection of

cheaters). First, we give a necessary condition of adversary structures for which perfectly robust NI-PE with small communication complexity exists. More precisely, we show that for any positive integers $n$, $m$ and $d>1$, an $n$-player access structure $U$, and an $n$-player adversary structure $T$, there exists a $U$-participating NI-PE scheme for $m$-variate polynomials over a finite field $F$ with $T$-private inputs such that (1) perfectly robust (i.e., successful cheating probability $\\epsilon=0$), (2) any polynomial of degree $d$ can be evaluated, and (3) the total size of shares of the output for some participating set is $o(m)\\times \\log |F|$, {\\em only if} $T$ is of type $Q_{d+1}$ for $U$, meaning that no $d+1$ sets in $T$ cover any set in $U$. Second, we give constructions of perfectly robust NI-PE schemes against threshold adversary and general adversary, respectively. All the proposed schemes ensure perfect robustness against $Q_{d+1}$ adversary, and computability of arbitrary polynomial of degree $d$. Third, we show that efficient robust NI-PE schemes against general adversary can be constructed by allowing cheaters very small chance of successful cheating. Namely, we construct two robust NI-PE schemes with $\\epsilon=1/|F|$ and the total size for shares of the output is only three times larger compared to the perfectly robust NI-PE scheme against threshold adversary.



01:17 [Pub][ePrint] CCA-Secure IB-KEM from Identity-Based Extractable Hash Proof Systems, by Yu Chen and Zongyang Zhang and Dongdai Lin and Zhenfu Cao

  In this paper, we introduce a general paradigm called identity-based extractable hash proof system (IB-EHPS), which is an extension of extractable hash proof system (EHPS) proposed by Wee (CRYPTO \'10). We show how to construct identity-based key encapsulation mechanism

(IB-KEM) from IB-EHPS in a simple and modular fashion. Our construction provides a generic method of building and interpreting CCA-secure IB-KEMs based on computational assumptions.

As instantiations, we realize IB-EHPS from the bilinear Diffie-Hellman assumption and the modified bilinear Diffie-Hellman assumption, respectively.



01:17 [Pub][ePrint] New Smooth Projective Hash Functions and One-Round Authenticated Key Exchange, by Fabrice Ben Hamouda and Olivier Blazy and C{\\\'e}line Chevalier and David Pointcheval and Damien Vergnaud

  Password-Authenticated Key Exchange (PAKE) has received deep

attention in the last few years, with a recent strong improvement by

Katz-Vaikuntanathan, and their one-round protocol: the two players just have to send simultaneous flows to each other, that depend on their own passwords only, to agree on a shared high entropy secret key. We follow their work with a further study of their new Smooth-Projective Hash Function framework, and namely we introduce new efficient instantiations on IND-CCA ciphertexts.

It allows us to design the most efficient PAKE known so far: a

one-round PAKE with two simultaneous flows consisting of 6 group elements each only, in any DDH-group.

Our scheme resists off-line dictionary attacks in the

Bellare-Pointcheval-Rogaway model, under the DDH assumption with a CRS.

We thereafter show how our new instantiations can prove more complex equations.

We then apply them to propose quite efficient instantiations in

the standard model of the more general family of protocols, termed

Langage-Authenticated Key Exchange.

They include quite concrete key exchange protocols, such as PAKE,

Verifier-based PAKE and Secret Handshakes.

In Verifier-based PAKE, the server knows a transformation of the password only, which limits impact of the corruption of the server, since exhaustive search would still have to be performed to recover the actual passwords.

In Secret Handshakes, two members of the same group want to identify each other secretly, in the sense that each party reveals his affiliation to the other only if they are members of the same group. Outsiders do not learn anything about the outcome of the protocol.