International Association for Cryptologic Research

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2014-09-16
18:17 [Pub][ePrint]

We investigate the hardness of finding solutions to bivariate polynomial congruences modulo RSA composites. We establish necessary conditions for a bivariate polynomial to be one-way, second preimage resistant, and collision resistant based on arithmetic properties of the polynomial. From these conditions we deduce a new computational assumption that implies an efficient algebraic collision-resistant hash function. We explore the assumption and relate it to known computational problems. The assumption leads to (i) a new statistically hiding commitment scheme that composes well with Pedersen commitments, (ii) a conceptually simple cryptographic accumulator, and (iii) an efficient chameleon hash function.

18:17 [Pub][ePrint]

A constrained pseudo random function (PRF) behaves like a standard PRF, but with the

added feature that the (master) secret key holder, having secret key K, can produce a constrained key, K_f, that allows for the evaluation of the PRF on a subset of the domain as determined by a predicate function f within some family F. While previous constructions gave constrained PRFs for poly-sized circuits, all reductions for such functionality were based in the selective model of security where an attacker declares which point he is attacking before seeing any constrained keys.

In this paper we give new constrained PRF constructions for circuits that have polynomial reductions to indistinguishability obfuscation in the random oracle model. Our solution is constructed from two recently emerged primitives: an adaptively secure Attribute-Based

Encryption (ABE) for circuits and a Universal Parameters as introduced by Hofheinz et al.

Both primitives are constructible from indistinguishability obfuscation (iO)

(and injective pseudorandom generators) with only polynomial loss.

18:17 [Pub][ePrint]

Shor\'s factoring algorithm uses two quantum registers. By introducing more registers we show that the measured numbers in these registers which are of the same pre-measurement state, should be equal if the original Shor\'s complexity argument is sound. This contradicts the argument that the second register has $r$ possible measured values.

There is an anonymous comment which argues that the states in these registers are entangled. If so, the entanglement involving many quantum registers can not be interpreted by the mechanism of EPR pairs and the like. In view of this peculiar entanglement has not yet been mentioned and investigated, we think the claim that the Shor\'s algorithm runs in polynomial time needs more physical verifications. We also discuss the problem to certify quantum computers.

18:17 [Pub][ePrint]

SipHash is an ARX based message authentication code developed by Aumasson and Bernstein. SipHash was designed to be fast on short messages. Already, a lot of implementations and applications for SipHash exist, whereas the cryptanalysis of SipHash lacks behind. In this paper, we provide the first published third-party cryptanalysis of SipHash regarding differential cryptanalysis. We use existing automatic tools to find differential characteristics for SipHash. To improve the quality of the results, we propose several extensions for these tools to find differential characteristics. For instance, to get a good probability estimation for differential characteristics in SipHash, we generalize the concepts presented by Mouha et al. and Velichkov et al. to calculate the probability of ARX functions. Our results are a characteristic for SipHash-2-4 with a probability of $2^{-236.3}$ and a distinguisher for the Finalization of SipHash-2-4 with practical complexity. Even though our results do not pose any threat to the security of SipHash-2-4, they significantly improve the results of the designers and give new insights in the security of SipHash-2-4.

09:18 [Job][New]

Our new Research Fellowship Scheme has been established to attract outstanding and ambitious researchers from across the globe to join Queen\'s University. The support that will be available for the Fellows is exceptional enabling them to become leaders in their field. Queen’s Fellows will initiate, develop and manage high level research projects in line with the University\'s research strategy. As such the scheme is aligned to the University\'s vision that is based on world class leadership in the pursuit of excellence which is relevant to society.

This prestigious four year Research Fellowship is a fantastic opportunity to build upon the foundations of an academic career and will lead to an academic post, subject to performance. The purpose of the scheme is to support the Fellows in pursuing their research. There will be a lighter teaching load and administration responsibilities during the award. Some teaching responsibilities will be introduced into the role to ensure the post-holder can transition appropriately to an academic post.

To support our ambitious research strategy we are currently making a substantial investment in our priority research areas and expect to award 20 fellowships at this time

Applicants with research expertise in Cyber Security are encouraged to apply. The salary scale for the posts is Ac3 £38,511 - £50,200 per annum (including contribution points).

07:44 [Pub]

The proceedings of CHES 2014 are now available online. IACR members can access them from http://www.iacr.org/proceedings/ with their IACR login.

2014-09-15
15:17 [Event][New]

Submission: 28 September 2014
From April 26 to April 30
Location: Sofia, Bulgaria

01:14 [Job][New]

The Interdisciplinary Research (IR) Lab in the Department of Computer Science at Southern Illinois University Carbondale (SIUC) is looking for talented and highly motivated PhD students.

The IR Lab explores interesting and exciting research areas on the intersection of computer and social sciences ranging from computer security and privacy, applied cryptography, game theory, big data analysis and software development to economics, psychology and cognitive science. Our interdisciplinary setting provides attractive and flexible research environment for brilliant and creative PhD candidates.

Currently, there are many active projects in the IR lab among which are: computational models of trust and influence mimicking human reasoning, securely computable economic model, game theory and economic aspects of security and privacy, design and analysis of sealed-bid auction protocols, and computational models of collaboration by social networks analysis and mining.

The successful candidates perform research on the aforementioned projects based on their experience and research interests. They must have strong background in Computer Science and/or Mathematics. They are expected to publish articles in well-known conferences and journals. Although all applications will be carefully evaluated, candidates with prior publications as well as research experience in the following areas are specifically encouraged to apply: secret sharing, secure multiparty computation, rational cryptography, game theory and computational or mathematical modeling.

Financial support and tuition waiver are provided for these positions and they will remain open until filled.

2014-09-12
09:17 [Pub][ePrint]

Security is the biggest concern in Wireless Sensor Networks (WSNs) especially for the ones which are deployed for military applications and monitoring. They are prone to various attacks which degrades the network performance very rapidly. Sometimes multiple attacks are launched in the network using hybrid anomaly. In this situation it is very difficult to find out which kind of anomaly is activated. In this paper, we have proposed a hybrid anomaly detection technique with the application of k-means clustering. The analysis of the network data set consists of traffic data and end to end delay data is performed. The data set is clustered using weka 3.6.10. After clustering, we get the threshold values of various network performance parameters (traffic and delay). These threshold values are used by the hybrid anomaly detection technique to detect the anomaly. During the experimentation, it has been observed that two types of anomalies are activated in the network causing misdirection and blackhole attacks.

09:17 [Pub][ePrint]

We consider the problem of designing multi-tenant public infrastructure clouds

resistant to cross-VM attacks without relying on single-tenancy or on

assumptions about the cloud\'s servers. In a cross-VM attack (which have

been demonstrated recently in Amazon EC2) an adversary launches malicious

virtual machines (VM) that perform side-channel attacks against co-located VMs

in order to recover their contents.

We propose a formal model in which to design and analyze \\emph{secure}

VM placement algorithms, which are online vector bin packing

algorithms that simultaneously satisfy certain optimization

constraints and notions of security. We introduce and formalize several notions

of security, establishing formal connections between them. We also introduce a

new notion of efficiency for online bin packing algorithms that better captures

their cost in the setting of cloud computing.

Finally, we propose a secure placement algorithm that achieves our strong

notions of security when used with a new cryptographic mechanism we refer to as

a shared deployment scheme.

2014-09-11
09:17 [Pub][ePrint]

In this short paper, we present a Fiat-Shamir type transform that takes any Sigma protocol for a relation $R$ and outputs a non-interactive zero-knowledge proof (not of knowledge) for the associated language $L_R$, in the common reference string model. As in the Fiat-Shamir transform, we use a hash function $H$. However, zero-knowledge is achieved under standard assumptions in the common reference string model (without any random oracle), and soundness is achieved in the \\emph{non-programmable} random oracle model. The concrete computational complexity of the transform is only slightly higher than the original Fiat-Shamir transform.