208 resultados para Provable Security


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Most previous work on unconditionally secure multiparty computation has focused on computing over a finite field (or ring). Multiparty computation over other algebraic structures has not received much attention, but is an interesting topic whose study may provide new and improved tools for certain applications. At CRYPTO 2007, Desmedt et al introduced a construction for a passive-secure multiparty multiplication protocol for black-box groups, reducing it to a certain graph coloring problem, leaving as an open problem to achieve security against active attacks. We present the first n-party protocol for unconditionally secure multiparty computation over a black-box group which is secure under an active attack model, tolerating any adversary structure Δ satisfying the Q 3 property (in which no union of three subsets from Δ covers the whole player set), which is known to be necessary for achieving security in the active setting. Our protocol uses Maurer’s Verifiable Secret Sharing (VSS) but preserves the essential simplicity of the graph-based approach of Desmedt et al, which avoids each shareholder having to rerun the full VSS protocol after each local computation. A corollary of our result is a new active-secure protocol for general multiparty computation of an arbitrary Boolean circuit.

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Espionage, surveillance and clandestine operations by secret agencies and governments were something of an East–West obsession in the second half of the twentieth century, a fact reflected in literature and film. In the twenty-first century, concerns of the Cold War and the threat of Communism have been rearticulated in the wake of 9/11. Under the rubric of ‘terror’ attacks, the discourses of security and surveillance are now framed within an increasingly global context. As this article illustrates, surveillance fiction written for young people engages with the cultural and political tropes that reflect a new social order that is different from the Cold War era, with its emphasis on spies, counter espionage, brainwashing and psychological warfare. While these tropes are still evident in much recent literature, advances in technology have transformed the means of tracking, profiling and accumulating data on individuals’ daily activities. Little Brother, The Hunger Games and Article 5 reflect the complex relationship between the real and the imaginary in the world of surveillance and, as this paper discusses, raise moral and ethical issues that are important questions for young people in our age of security.

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This paper makes a formal security analysis of the current Australian e-passport implementation using model checking tools CASPER/CSP/FDR. We highlight security issues in the current implementation and identify new threats when an e-passport system is integrated with an automated processing system like SmartGate. The paper also provides a security analysis of the European Union (EU) proposal for Extended Access Control (EAC) that is intended to provide improved security in protecting biometric information of the e-passport bearer. The current e-passport specification fails to provide a list of adequate security goals that could be used for security evaluation. We fill this gap; we present a collection of security goals for evaluation of e-passport protocols. Our analysis confirms existing security weaknesses that were previously identified and shows that both the Australian e-passport implementation and the EU proposal fail to address many security and privacy aspects that are paramount in implementing a secure border control mechanism. ACM Classification C.2.2 (Communication/Networking and Information Technology – Network Protocols – Model Checking), D.2.4 (Software Engineering – Software/Program Verification – Formal Methods), D.4.6 (Operating Systems – Security and Privacy Protection – Authentication)

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In this article, we study the security of the IDEA block cipher when it is used in various simple-length or double-length hashing modes. Even though this cipher is still considered as secure, we show that one should avoid its use as internal primitive for block cipher based hashing. In particular, we are able to generate instantaneously free-start collisions for most modes, and even semi-free-start collisions, pseudo-preimages or hash collisions in practical complexity. This work shows a practical example of the gap that exists between secret-key and known or chosen-key security for block ciphers. Moreover, we also settle the 20-year-old standing open question concerning the security of the Abreast-DM and Tandem-DM double-length compression functions, originally invented to be instantiated with IDEA. Our attacks have been verified experimentally and work even for strengthened versions of IDEA with any number of rounds.

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The increasing growth in the use of Hardware Security Modules (HSMs) towards identification and authentication of a security endpoint have raised numerous privacy and security concerns. HSMs have the ability to tie a system or an object, along with its users to the physical world. However, this enables tracking of the user and/or an object associated with the HSM. Current systems do not adequately address the privacy needs and as such are susceptible to various attacks. In this work, we analyse various security and privacy concerns that arise when deploying such hardware security modules and propose a system that allow users to create pseudonyms from a trusted master public-secret key pair. The proposed system is based on the intractability of factoring and finding square roots of a quadratic residue modulo a composite number, where the composite number is a product of two large primes. Along with the standard notion of protecting privacy of an user, the proposed system offers colligation between seemingly independent pseudonyms. This new property when combined with HSMs that store the master secret key is extremely beneficial to a user, as it offers a convenient way to generate a large number of pseudonyms using relatively small storage requirements.

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Recently a new human authentication scheme called PAS (predicate-based authentication service) was proposed, which does not require the assistance of any supplementary device. The main security claim of PAS is to resist passive adversaries who can observe the whole authentication session between the human user and the remote server. In this paper we show that PAS is insecure against both brute force attack and a probabilistic attack. In particular, we show that its security against brute force attack was strongly overestimated. Furthermore, we introduce a probabilistic attack, which can break part of the password even with a very small number of observed authentication sessions. Although the proposed attack cannot completely break the password, it can downgrade the PAS system to a much weaker system similar to common OTP (one-time password) systems.

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This paper provides a detailed description of the current Australian e-passport implementation and makes a formal verification using model checking tools CASPER/CSP/FDR. We highlight security issues present in the current e-passport implementation and identify new threats when an e-passport system is integrated with an automated processing systems like SmartGate. Because the current e-passport specification does not provide adequate security goals, to perform a rational security analysis we identify and describe a set of security goals for evaluation of e-passport protocols. Our analysis confirms existing security issues that were previously informally identified and presents weaknesses that exists in the current e-passport implementation.

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The final report for the ARC project "Airports of the Future". It contains the findings and recommendations provided by the various teams to the industry partners.

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Security protocols are designed in order to provide security properties (goals). They achieve their goals using cryptographic primitives such as key agreement or hash functions. Security analysis tools are used in order to verify whether a security protocol achieves its goals or not. The analysed property by specific purpose tools are predefined properties such as secrecy (confidentiality), authentication or non-repudiation. There are security goals that are defined by the user in systems with security requirements. Analysis of these properties is possible with general purpose analysis tools such as coloured petri nets (CPN). This research analyses two security properties that are defined in a protocol that is based on trusted platform module (TPM). The analysed protocol is proposed by Delaune to use TPM capabilities and secrets in order to open only one secret from two submitted secrets to a recipient

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INTRODUCTION Globally, one-third of food production is lost annually due to negligent authorities. India alone loses some 21 million tonnes of wheat per year even while it has 200 million food-insecure people in the nation. Disturbingly provocative as it may sound, it is amazing how national and international institutions and governments make use of human hunger for their own survival (Raghib 2013). The global food system is increasingly insecure. Challenges to long-term global food security are encapsulated by resource scarcity, environmental degradation, biodiversity loss, climate change, reductions of farm labour and a growing world population. These issues are caused and aggravated by the spread of corporatised and monopolised food systems, dietary change, and urbanisation. These factors have rapidly brought food insecurity under the umbrella of unconventional security threats (Heukelom 2011). For some, humanitarian crises associated with food insecurity, or what has been dubbed ‘the silent tsunami’, is a pending peril, notably for the world’s poorest and most vulnerable people. For others, the food production industry is an emerging market with unprecedented profits. Despite this problem of food scarcity we are witnessing extraordinary ‘food wastage’, notably in North America and Europe, on a scale that would reportedly be capable of feeding the world’s hungry six times over (Stuart 2012). As the opening quotation to this chapter suggests, governments and corporations are deeply involved in the contexts, politics, and resources associated with food related issues. As many economically developed and advanced industrial nations are reporting a rise out of recession, announcements are made by the world’s richest countries that they are to cut $US2 billion per year from food aid. The head of the World Food Aid Programme, Rosette Sheeran, warns that such cuts could result in ‘the loss of a generation’ (Walters 2011). The global food crisis has also reinvigorated debates about agricultural development and genetically modified (GM) food; as well as fuelling debates about poverty, debt and security. This chapter provides a discussion of the political economy of global food debates and explores the threats and opportunities surrounding food production and future food security.

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International Relations’ engagement with global health governance has proliferated in the last decade. There are a number of excellent works that seek to understand how the relationship between politics and health shapes and informs people’s lives and governments’ policies. However, the overt securitization of health by the IR field has, Biosecurity interventions argues, remained relatively unproblematized...

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Distributed Network Protocol Version 3 (DNP3) is the de-facto communication protocol for power grids. Standard-based interoperability among devices has made the protocol useful to other infrastructures such as water, sewage, oil and gas. DNP3 is designed to facilitate interaction between master stations and outstations. In this paper, we apply a formal modelling methodology called Coloured Petri Nets (CPN) to create an executable model representation of DNP3 protocol. The model facilitates the analysis of the protocol to ensure that the protocol will behave as expected. Also, we illustrate how to verify and validate the behaviour of the protocol, using the CPN model and the corresponding state space tool to determine if there are insecure states. With this approach, we were able to identify a Denial of Service (DoS) attack against the DNP3 protocol.

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