Jonathan Zinzi Ayitey, Elias Danyi Kuusaana, Joseph Kwaku Kidido
The growth of Africa’s towns and cities has outpaced local authority capacity in terms of management, infrastructure and financing. Many African towns and cities are now facing a governance crisis. Accordingly, the capability and capacity of urban local government to provide basic services to a growing population have entered the core of the development debate. In particular, fiscal decentralization has become a main theme of urban governance in recent years. This paper presents an overview of how property rating can be harnessed to create the bulk of revenue needed for local level development within identified challenges. Several challenges were identified to be militating against efficient and effective implementation of property rates in the Wa Municipality. These included poor property data system, political interferences, non-enforcement of the law on rate defaulters, low budget deficit in financing revaluation, insufficient staffing and low level technical capacity of the few staff available at the Municipal Land Valuation Division and Rating Unit of the Assembly. Field data revealed that, even within these numerous constraints to property rating identified generally in Ghana and especially in the Wa Municipality, property rating can generate up to 30% of the current budget of the Wa Municipality Assembly (WMA). This is possible, provided the current challenges are streamlined, much investment made in the rating and valuation units and management attention drawn towards improving property rating.
Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., network, servers, storage, applications and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. During the last a few years, data security and integrity in cloud computing has emerged as a significantly important research area that has attracted increasing attention from both industry and academia. The virtual environment of cloud computing allows users to access computing power that exceeds what is contained within their own physical worlds. To enter this virtual environment, cloud users must transfer data throughout the cloud. Typically, cloud users know neither the exact location of their data nor the other sources of the data collectively stored with theirs. Consequently, several data security and integrity concerns have arisen, including key management, access control, searchable encryption techniques, remote integrity checks and proof of ownership in the cloud.\nThe first aspect of the work presented in this thesis is tree-based key management in cloud computing. Data encryption before outsourcing to the cloud is a common way to protect data privacy. Thus, key management is a challenging issue in cloud computing. It is the ability to correctly assign, monitor and secure keys which defines the level of operational security provided by any encryption implementation. The fundamental idea of this work is to design a secure and flexible key management mechanism for the outsourced data in cloud computing. In this thesis, an innovative tree-based key management scheme is proposed. The outsourced database remains private and secure, while some selected data and key nodes are shared with other parties in the cloud. Flexibility of key management is achieved and the security is proved in the standard model.\nThe second aspect of the work presented in this thesis is fine-grained access control. In order to secure the outsourced data in the cloud, designing efficient and secure access control is a challenging issue. Unlike traditional access control in which the data users and storage servers are in the same trust domain, access control techniques are very different in cloud computing, as the cloud servers are not trusted by most cloud users. The key idea of this work is to attribute sets-based access control. This thesis points out that any access policy can be defined as a logical expression formula over different attribute sets. Logical expression indicates what kind of user is allowed to access the data. A fine-grained and efficient access control is proposed, based on logical expression.\nThe third aspect of the work presented in this thesis is efficient searchable encryption techniques in cloud computing. Because the data is usually encrypted before being outsourced to the cloud, searching the encrypted data in cloud computing has recently gained attention and led to the development of efficient searchable encryption techniques. The fundamental idea of this work is to reduce the search cost on encrypted data. In this thesis, a practical keyword searching mechanism is proposed. The solution is very simple. It enables efficient multi-user keyword searches and hides the private information in the search queries. The security is proved in the standard model.\nThe fourth aspect of the work presented in this thesis is public remote data integrity checks. As the clients store important data in remote cloud storage without a local copy, it is important to check the remote data integrity. Design of efficient remote integrity check protocols without downloading the data is a challenging issue in cloud computing. The key idea of this work is a public remote integrity check based on zero-knowledge proof. In this thesis, an innovative public remote integrity check scheme (PRIC) is proposed. No information of either the verified data or the homomorphic tags is leaked. In addition, the experiment result shows that PRIC is efficient, especially when the data size is large or the integrity check is frequent. The security of PRIC is proved in the random oracle model.\nThe last aspect of the work presented in this thesis is proof of multiparty ownership for encrypted data in the cloud. There are many applications of ownership sharing by different users and the design of the proof protocols of joint ownership is a challenging issue. Meanwhile, the design of proof-of-ownership mechanisms for encrypted data is even more difficult. This is because encryption of the same file by different users with random keys results in different ciphertexts, and the cloud server cannot store the same hash root value for ownership verification. In this thesis, a proof of multiparty ownership solution (PMOW) with encrypted data is proposed. Every user can prove that he/she holds the plaintext of the encrypted file when the server stores one ciphertext only. In addition, a PMOW system is constructed. The security of PMOW is proved in the ideal cipher model.\nThe major contribution of this thesis is innovative and improved approaches to secure data in cloud computing. Using these approaches developed, a trustworthy cloud environment can be achieved.
Purpose: The main aim of this paper is to show the Polish health care system’s transformation process in recent years and to answer the question whether is there a simple path from centralization to decentralization or another form of centralization. The transformation process has changed the health care system’s financing from budget planning to compulsory health insurance deducted from workers’ and employers’ premiums. In addition, the transformation has strengthened the autonomy of the health care at a local level and made it less dependent from the public sector. Different health care system corresponds to each period respectively. It is believed that the main change in Polish health care took place in 1999 when the function of the payer which formerly belonged to the government administration was overtaken by an independent institution (Health Care Fund). The article not only describes and explains functioning of each health care model existing in Poland in the past but also puts them in the international context. In addition, the article shows difficulties each model had to face and cope with and indicates the underlying reasons for changes in the Polish health care and theirs consequences. Design/methodology/approach: A range of recently published (1990-2012) works, which aim to provide both theoretical and practical view on the health care system in Poland, has been analyzed. Findings: The final thesis stated in this article presents a way of interpretation changes that the Polish health care system has been undergoing in recent years. This paper challenges a thesis according to which the polish health care system is decentralized. Research limitations/implications: The scope of this article is limited and does not allow to perform further research. Additionally, the research was based on the very scare literature on the issue of health care system in transition. Practical implications: This paper reveals several practical applications worthy of future
Georg Neugebauer, Lucas Brutschy, Ulrike Meyer, Susanne Wetzel
Abstract. The problem of fair and privacy-preserving ordered set reconciliation arises in a variety of applications like auctions, e-voting, and appointment reconciliation. While several multi-party protocols have been proposed that solve this problem in the semi-honest model, there are no multi-party protocols that are secure in the malicious model so far. In this paper, we close this gap. Our newly proposed protocols are shown to be secure in the malicious model based on a variety of novel non-interactive zero-knowledge-proofs. We describe the implementation of our protocols and evaluate their performance in comparison to protocols solving the problem in the semi-honest case.
Abstract. Verifiably encrypted signatures (VES) are signatures encrypted by a public key of a trusted third party and we can verify their validity without decryption. This paper proposes a new VES scheme which is secure under the decisional linear (DLIN) assumption in the standard model. We also propose new obfuscators for encrypted signatures (ES) and encrypted VES (EVES) which are secure under the DLIN assump-tion. All previous efficient VES schemes in the standard model are either secure under standard assumptions (such as the computational Diffie-Hellman assumption) with large verification (or secret) keys or secure under (non-standard) dynamic q-type assumptions (such as the q-strong Diffie-Hellman extraction assumption) with short verification keys. Our construction is the first efficient VES scheme with short verification (and secret) keys secure under a standard assumption (DLIN). As by-products of our VES scheme, we construct new obfuscators for ES/EVES based on our new VES scheme. They are more efficient than previous obfuscators with respect to the public key size. Previous ob-fuscators for EVES are secure under non-standard assumption and use zero-knowledge (ZK) proof systems and Fiat-Shamir heuristics to obtain non-interactive ZK, i.e., its security is considered in the random oracle model. Thus, our construction also has an advantage with respect to as-sumptions and security models. Our new obfuscator for ES is obtained from our new obfuscator for EVES.
Decentralized or distributed small renewable power facilities are usually installed in local communities for households and small business companies. These facilities include solar PV, concentrated solar power, and wind power, etc. In order to promote installations of such facilities, governments in many countries have developed a number of policies and business models. For example, in Germany and Canada, electricity feed-in tariff policy and business model were developed; in the USA, tax rebate policies and relevant business models were promoted. These policies and models have in some but not in large scale promoted decentralized small renewable power in local communities. The key issue is that these policies and business models do not provide sufficient incentives to local distribution companies (LDC), nor to renewable power installers and users. This paper’s research covers the creation of a business and communication model, named as LDC model, to incentivize both renewable power installers/users and LDCs. This LDC model can play a key role in promoting decentralized small-scale generation (DSG) with renewable energy in local communities. The core element of the LDC model is a revenue model which serves as an instrument to finance renewable installations for households and small commercial businesses. A case study is undertaken with real data of a power distribution company in Toronto, Canada. This paper concludes that with appropriate government policy and with the development of customized information systems for accessing households and small business via internet, an LDC will be able to take leadership in investing and installing small renewable power, and consequently enlarge the share of renewable energy supply in its local power distribution network.
The aim of this chapter is to critically describe the evolution of the Spanish National Health System (NHS) in the last 25 years and its current situation. We will also revise the main reforms which are currently under debate. During these years, even with its ups and downs, the NHS has become a cornerstone of the Spanish welfare state. Mostly financed through taxes and with the predominance of public provision, the system has been able to incorporate the latest medical advances, offering quality health services almost universally. At the same time, in an ad hoc and rather hasty manner, the system has gone through a decentralization process that started with the devolution of health competences to the so-called historical regions, and was finally extended in 2002 to the 17 Spanish Autonomous Communities (ACs). These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
After 1990’s and the European integration, Romania faced major changes in the structure and finance of education. There are many decisions regarding the education reform, the decentralization of the public schools, and the curriculum. The education needs to evolve from an abstracted way to a practice way, it most avoids telling and learning things out of the context. The aim of this article is to review international projects current state in public secondary education and to analyze the premises of an integrated project management model, in the decentralized education system. Project management is common for all industries and areas, in different ways, dealing with complex projects or small one. Searching the best practices for the modern education development is an important objective for every government. So, from this perspective, the current study aims at reviewing the integration of the international projects in the schools agenda, evaluating the consolidation of the defining project management elements. The methodology involved a questionnaire-based research among school managers from Constanta County. The main beneficiary of the research study are the school managers and the local public administration institutions too.
Education, Management, Technology, Human Resources
Patrick Mamboko, Theo Tsokota, Maximillan Giyane, Charity Mhaka
The decentralization of local authorities in Zimbabwe has resulted in local authorities being thrown to the deep end in terms of meeting societal needs. The ever increasing population coupled with the financial crisis both on the global stage and at local level makes it difficult for Zimbabwean local authorities to continue relying on traditional sources of finance for service delivery, sustainability and social development. The aim of the study was to explore alternative financing options and to gain an insight into administrative and legal systems that negate Gweru City Council’s revenue mobilization strategies. The data was collected using document review and follow up interviews with the Treasury personnel. It was noted that the legal and administrative systems were major impediments in the quest for local authority to boost its revenue base. This calls for the expansion of existing revenue sources and development of a policy framework which encourages Public-Private Partnerships.
Recently,more and more people are quite attracted to a new digital currency which is called Bitcoin because of its anonymity,non-central authority,limited total amount,low transaction cost and free? convertibility.However,it could cause problems or risk of speculation,cyber crime,the waste of resource,the huge fluctuation in the price and so on.The emergence of Bitcoin is attributed to technical,economic and social factors.So rather than in just one aspect,Bitcoin should be concerned in different aspects,such as research,education and governance.
Now a days for every data transfer between any sites we are using cloud data transfer instead of distributed data transfer. so we must concentrate on security. Provable data possession (PDP) is a technique which used for integrity of data in storage outsourcing. In this paper,we present a schema for the construction of an efficient PDP scheme for distributed cloud storage to support the scalability of service and datamigration, in which we consider the existence of multiple cloud service providers to cooperatively store and maintain the clients’ data. We present a cooperative PDP (CPDP) scheme based on verifiable response using cryptographic and hash index hierarchy. The security of our scheme based on multi-prover, zero-knowledge proof system, which can satisfy completeness,knowledge soundness, and zero-knowledge properties. We are using AES method for cryptographic. Our experiments show that our solution introduces lower computation and communicationoverheads in comparison with non-cooperative approaches. IndexTerms: Storage Security, Provable Data Possession, Zero-knowledge, cryptography, Multiple Cloud, CooperativeProvable Data Possession, encryption, AES algorithm.
The SHARE Compliance Profiles consist of a set of quality control indicators based on the SHARE Survey Specifications. All participating countries are evaluated on these indicators uniformly, although the environments for conducting the survey differ among European countries. As an ex-ante harmonized endeavor like SHARE cannot afford to set country-specific standards on what qualifies as good performance the combination of ex-ante Survey Specifications and ex-post Compliance Profiles levels the playing field for all participating countries and allows for a fair comparison of national survey quality. This document reports how SHARE quality standards were adhered to in Wave 4. Section 2 lists the survey agencies involved in Wave 4. Section 3 describes the data input for this evaluation. Section 4 reports the results in form of the various indicators. It is important to note that Wave 4 of SHARE was a difficult wave since it was the first wave under the new decentralized funding scheme. As opposed to the three earlier waves, survey operations in each country were financed nationally and not centrally by the EU Commission. This has put the ex-ante harmonization approach under additional pressure, not the least due to the difficulties of some countries to provide the necessary funds in time. The compliance profiles in this report therefore do not only reflect differences in survey agency performance but also the pressures of time and money in the SHARE member countries.
Abstract. We present a set of new, efficient, universally composable two-party protocols for evaluating reactive arithmetic circuits modulo n, where n is a safe RSA modulus of unknown factorization. Our protocols are based on a homomorphic encryption scheme with message space Zn, zero-knowledge proofs of existence, and a novel “mixed ” trapdoor commitment scheme. Our protocols are proven secure against adaptive corruptions (assuming secure erasures) under standard assumptions in the CRS model (without random oracles). Our protocols appear to be the most efficient ones that satisfy these security requirements. In contrast to prior protocols, we provide facilities that allow for the use of our protocols as building blocks of higher-level protocols. An additional contribution of this paper is a universally composable construction of the variant of the Dodis-Yampolskiy oblivious pseudorandom function in a group of order n as originally proposed by Jarecki and Liu.
Abstrak
Penelitian ini bertujuan untuk memperoleh informasi tentang dukungan pemerintah kota Surabaya dan dampaknya dalam pelaksanaan pendidikan wajib belajar 12 tahun di Kota Surabaya. Pendidikan menjadi tanggung jawab pemerintah daerah merupakan konsekuensi dari adanya desentralisasi pendidikan. Pelaksanaan pendidikan dari sentralisasi ke desentralisasi membuat pemerintah daerah memiliki kewenangan yang nyata dan luas dalam hal perencanaan, pelaksanaan, dan pembuatan kebijakan pendidikan di wilayahnya. Penelitian ini dilakukan di lima sekolah menegah dan kejuruan yang ada di Surabaya, dengan sumber data dinas pendidikan kota Surabaya, pengamat pendidikan, kepala sekolah dan guru di sekolah menengah dan kejuruan. Pengumpulan data dilakukan melalui studi dokumentasi, observasi, dan wawancara. Data yang diperoleh dianalisis secara deskriptif kualitatif. Hasil penelitian menunjukkan 1) Dukungan pemerintah pada pelaksanaan wajib belajar 12 tahun di Surabaya dengan pemberian Biaya Operasional Pendidikan Daerah (BOPDA) mulai pendidikan dasar hingga pendidikan menengah negeri dan Hibah BOPDA pada sekolah swasta; 2) Pelaksanaan program BOPDA berdampak postif pada peningkatkan akses pendidikan untuk masyarakat kota Surabaya dan berdampak adanya kuota bagi masyarakat luar kota Surabaya; 3) Dampak BOPDA pada pelaksanaan pendidikan di tingkat sekolah menengah dan kejuruan berpengaruh pada manajemen pelaksanaan ditingkat sekolah, antara lain kebijakan sekolah dalam hal pembiayaan, kondisi sarana dan prasarana pembelajaran, partisipasi siswa dalam pembelajaran dan ekstrakulikuler, serta partisipasi Orangtua.
Abstract
This study aimed to obtain information on the government of Surabaya’s support and it impact on the implementation of the 12-year compulsory education in Surabaya. Education as the responsibility of local government is a consequence of the decentralization of education. Implementation of education from centralization to decentralization make local governments have the authority to do many things as they wish in terms of planning, implementing, and education policy-making in the region. The research was conducted in five secondary schools and vocational in Surabaya, with data sources from Surabaya Education office, education observers, principals and teachers in secondary and vocational schools. Data collected through the study documentation, observation, and interviews. Data were analyzed by descriptive qualitative. The results showed 1) the support of the government on the implementation of the 12- years compulsory education in Surabaya administration Education Operational Area (BOPDA) from primary education to secondary education in public school and the grant of BOPDA for the private school; 2) Implementation of the BOPDA program has positive impact on increasing access to education for the society of Surabaya and affect the quota for the society outside Surabaya; 3) The impact of BOPDA on the implementation of education at secondary school level and vocational affect on management implementation at the school, such as the school s policy in terms of financing, infrastructure conditions of learning, participation students in learning, extracurricular and parent participation.
Bitcoin in its currency essence and at the technical level can be used to build a safe,reliable decentration payment system so that the problems in electronic money with multiple payment bills can be solved.From the analysis of the application level,the bitcoin has shortage in trust,illegal trading,deflation,and decentration.Considering the influence of bitcoin on the current financial system and the implications for future development,researches on bitcoin should be strengthened by the research institutions and the International Monetary Fund.The currency theory and application of bitcoin should be explored further.Governments and central banks should face the scientific and revolutionary of bitcoin.Technical departments and legislative bodies should strengthen researches and legislation supervision of bitcoin,and solve the problem of the initial allocation of currency.
Michael Backes, Aniket Kate, Sebastian Meiser, Tim Ruffing
Cryptographic protocols are commonly designed and their security proven under the assumption that the protocol parties have access to perfect (uniform) randomness. Physical randomness sources deployed in practical implementations of these protocols often fall short in meeting this assumption, but instead provide only a steady stream of bits with certain high entropy. Trying to ground cryptographic protocols on such imperfect, weaker sources of randomness has thus far mostly given rise to a multitude of impossibility results, including the impossibility to construct provably secure encryption, commitments, secret sharing, and zero-knowledge proofs based solely on a weak source. More generally, indistinguishability-based properties break down for such weak sources. In this paper, we show that the loss of security induced by using a weak source can be meaningfully quantified if the source is bounded, e.g., for the well-studied Santha-Vazirani (SV) sources. The quantification relies on a novel relaxation of indistinguishability by a quantitative parameter. We call the resulting notion dierential indistinguishability in order to reflect its structural similarity to dierential privacy. More concretely, we prove that indistinguishability with uniform randomness implies dierential indistinguishability with weak randomness. We show that if the amount of weak randomness is limited (e.g., by using it only to seed a PRG), all cryptographic primitives and protocols still achieve dierential indistinguishability.
Electronic voting is a popular application of cryptographic and network techniques to e-government. Most of the existing e-voting schemes can be classified into two categories: homomorphic voting and shuffling-based voting. In a homomorphic voting, an encryption algorithm with special homomorphic property (e.g. ElGamal encryption or Paillier encryption) is employed to encrypt the votes such that the sum of the votes can be recovered without decrypting any single vote. An advantage of homomorphic voting is efficient tallying. Tallying in homomorphic voting only costs one single decryption operation for each candidate. In this chapter, the existing e-voting solutions in both categories are surveyed and analysed. The key security properties in both categories are presented and then the existing e-voting schemes in each category are checked against the corresponding security properties. Security and efficiency of the schemes are analysed and the strongest security and highest efficiency achievable in each category is estimated. Problems and concerns about the existing solutions including vulnerability to malicious voters and (or) talliers, possible failure of complete correctness, imperfect privacy, dependence on computational assumptions, and exaggerated efficiency are addressed. New approaches will be proposed in both kinds of solutions to overcome the existing drawbacks in them. In homomorphic e-voting, the authors deal with possibly malicious voters and aim at efficient vote validity check to achieve strong and formally provable soundness and privacy. It can be implemented through new zero knowledge proof techniques, which are both efficient and provably secure. In mix-network-based e-voting, the authors deal with possibly deviating operations of both voters and talliers and aim at efficient proof of validity of shuffling, which guarantees the desired security properties and prevent attacks from malicious participants. It can be based on inspiring linear algebra knowledge and the new zero knowledge proof of existence of secret permutation.
In 2010, the fourth decade of the HIV pandemic arrived during a time of unprecedented success in HIV prevention. Globally, UNAIDS estimated that new HIV infections fell by 33% between 2001 and 2011; new infections among adults and adolescents fell by 50% or more in 26 countries (more than half of these countries were in sub-Saharan Africa), and new infections among children worldwide dropped by 52% [1,2]. The declines in new HIV infections are particularly evident in countries with sustained and more strategic investments, which take into account the specifics of local epidemics, increased political leadership and community engagement in response to the HIV epidemic, and scale up of HIV prevention and treatment programmes [2]. The rapidly growing delivery of antiretrovirals to women and infant feeding–based prevention programmes has resulted in a sharp decline in new HIV diagnoses among children. The encouraging declines in HIV infections can also be attributed to the improved effectiveness of combination antiretroviral treatment (cART), an expanded range of improved medications, the declining prices that make cART more accessible to people in low-income countries, growing coverage with HIV testing, and improved access to prevention and treatment services (particularly for women and young people in low-income countries). Global investment in the AIDS response jumped from US$3.8 billion in 2002 to US$18.9 billion in 2012. The new decade also saw a revolution in HIV prevention with ground-breaking scientific advances in HIV biomedical prevention, and specifically, proof that microbicides containing an antiretroviral agent can reduce sexual transmission of HIV to women by 39% [3], that earlier start of treatment by HIV-positive people (treatment as prevention or TasP) can reduce the risk of onward transmission by as much as 96% [4], and that consistent, correct use of a daily antiretroviral tablet by men who have sex with men (MSM) can achieve substantial reductions in HIV infections (pre-exposure prophylaxis or PrEP) [5]. In response to the excitement and optimism surrounding the preventative effects of antiretroviral medications, the UN member states considered and unanimously approved the new Political Declaration on HIV/AIDS at a special session of the General Assembly in New York in 2011 [6]. At the core of the 2011 UN Political Declaration are ambitious new HIV prevention targets calling on governments to commit to reducing sexual transmission of HIV by 50%, reducing HIV transmission though injecting drug use by 50% and eliminating mother-to-child transmission of HIV by 2015. These targets are aimed at reinvigorating the commitment towards achieving the Millennium Development Goal #6 to combat HIV/AIDS [7]. In the past two years, research on HIV biomedical prevention has focused on adapting the new prevention strategies to the context of local HIV epidemics [8]. There have been equal measures of optimism and pessimism expressed about the ability of new prevention strategies to halt the HIV pandemic. Based on the evidence that starting treatment earlier can increase health benefits and extend life for people with HIV [9,10], many clinicians are already recommending early treatment for both medical and TasP purposes. Regarding PrEP, the widespread reaction is caution in recommending this strategy. Such reluctance is based on concerns about the common adherence issues in the studies of PrEP [11], the obvious relationship between level of adherence to daily medication schedule and its preventative effect [12] and side effects and drug-resistant HIV [13], among others. Despite little evidence that PrEP use can affect behaviour, many concerns have been voiced about the future of safe sex practices, particularly condom use among MSM, if new biomedical prevention strategies are introduced. More research is needed to investigate this issue using appropriate study designs. In its current form, daily PrEP may benefit only a small number of people with very high and ongoing risk for HIV infection, and other PrEP regimens must be explored. The overarching concern about new prevention strategies, particularly PrEP, is that the cost and burden of providing them are currently unacceptable for most, even high-income, countries. As a result, there have been calls for more evidence and a very slow progress in implementing these two new exciting HIV prevention developments. Regarding PrEP, only two countries to date have prescription guidelines for people at high risk of HIV infection [14,15]. We now have the knowledge and new tools to revolutionize HIV prevention, and we have the bold new Political Declaration with ambitious targets. It must be acknowledged that the task of bringing HIV infections down to zero seems daunting from where we stand now in late 2013. Despite the global success in lowering the HIV infection rates by 33% [1], sub-Saharan Africa has seen only a 25% decline [16]. Some regions have seen increases (8% in Eastern Europe and central Asia [17], 19% in East Asia [18] and 37% in the Middle East and North Africa [19]). This lack of progress has been associated with insufficient resources, inadequate coverage of women with antiretroviral treatment and HIV testing programmes not reaching the population groups at high risk for HIV infection. While sexual behaviour has changed to become safer in some countries and populations, sexual risk taking has increased in other settings. This is the case in most high-income countries in North America, western and central Europe and Australasia, where MSM are central to local HIV epidemics. In these countries, both high-risk sexual practices among MSM and HIV infections have been on the rise [20,21]. Condom use has increased in some countries, but declined in others. Proven effective interventions (e.g., prevention of mother-to-child transmission (PMTCT) and needle- and syringe-exchange programmes) have not achieved sufficiently high coverage in many countries [1]. Although trends in risky sexual practices have been linked to the trends in HIV incidence [22] and population-level behaviour change to the reduction in HIV prevalence, there are still challenges in linking behaviour-change programmes to specific HIV outcomes on the population level [2]. While new expectations have been raised about the role of antiretrovirals for HIV prevention, mixed progress was observed in access to cART, and only 61% of people eligible for treatment under the 2010 WHO guidelines received it (this is as little as 34% under the 2013 WHO guidelines). The Political Declaration has for the first time named and acknowledged the importance of such population groups as MSM, people who inject drugs and sex workers for HIV prevention, but in many settings, stigma and access to treatment and prevention services for these groups are still important challenges. Many low- and middle-income countries have stepped up their local investments in HIV prevention [2], but, regrettably, the lack of resources has remained a major issue: only US$18.9 billion was available from all sources for the AIDS response in 2012, and this was estimated to be 16–26% short of annual need [1]. It is at this time of some successes in HIV prevention and challenges in how to optimize the available resources and tools that the aspirational Political Declaration of commitment to fight the pandemic is necessary. This year's International AIDS Day marks the midpoint towards the deadline set by the Political Declaration in 2011. It is an opportunity for governments and each of us to revisit and reinvigorate the universal commitment to bring HIV infections to zero. Like never before, we have good cause to expect the next generation to be AIDS-free and new HIV infections to move towards zero. In the face of the 75 million people who have suffered from HIV/AIDS and the many more affected, the international community should keep the promise and bring this HIV pandemic to an end. None were declared. The Kirby Institute receives project funding from the Australian Government Department of Health and Ageing. The views expressed in this publication do not necessarily represent the position of the Australian Government. IZ has prepared the manuscript and approved its final version.
Sherman S. M. Chow, Matthew Franklin, Haibin Zhang
Abstract. We reformalize and recast dual-receiver encryption (DRE) proposed in CCS ’04, a public-key encryption (PKE) scheme for encrypting to two independent recipients in one shot. We start by defining the crucial soundness property for DRE, which ensures that two recipients will get the same decryption result. While conceptually simple, DRE with soundness turns out to be a powerful primitive for various goals for PKE, such as complete non-malleability (CNM) and plaintext-awareness (PA). We then construct practical DRE schemes without random oracles under the Bilinear Decisional Diffie-Hellman assumption, while prior approaches rely on random oracles or inefficient non-interactive zero-knowledge proofs. Finally, we investigate further applications or extensions of DRE, including DRE with CNM, combined use of DRE and PKE, strengthening two types of PKE schemes with plaintext equality test, off-the-record messaging with a stronger notion of deniability, etc.
Cryptographic credentials allow user authorizations to be granted and verified. and have such applications as e-Passports, e-Commerce, and electronic cash. This thesis proposes a privacy protecting approach of binding biometrically derived keys to cryptographic credentials to prevent unauthorized lending. Our approach builds on the 2011 work of Adams, offering additional benefits of privacy protection of biometric information, generality on biometric modalities, and performance. Our protocol integrates into Brands’ Digital Credential scheme, and the Anonymous Credentials scheme of Camenisch and Lysyanskaya. We describe a detailed integration with the Digital Credential Scheme and sketch the integration into the Anonymous Credentials scheme. Security proofs for non-transferability, correctness of ownership, and unlinkability are provided for the protocol’s instantiation into Digital Credentials. Our approach uses specialized biometric devices in both the issue and show protocols. These devices are configured with our proposed primitive, the fuzzy ex-tractor indistinguishability adaptor which uses a traditional fuzzy extractor to create and regenerate cryptographic keys from biometric data and IND-CCA2 secure en-cryption protect the generated public data against multiplicity attacks. Pedersen commitments are used to hold the key at issue and show time, and A zero-knowledge proof of knowledge is used to ensure correspondence of key created at issue-time and regenerated at show-time. The above is done in a manner which preserves biometric privacy, as and delivers non-transferability of digital credentials. The biometric itself is not stored or divulged to any of the parties involved in the protocol. Privacy protection in multiple enrollments scenarios is achieved by the fuzzy extractor indistinguishability adapter. The zero knowledge proof of knowledge is used in the showing protocol to prove knowledge of values without divulging them.
In this article, we discuss a possible exploit in Bitcoin that arises from the simultaneous adoption of client versions 0.8.1 and 0.8.2 (or 0.8.3) in the network. In version 0.8.2, Bitcoin clients no longer accept transactions with non-strict signature encoding. As we show, this incompatibility with prior client versions can potentially lead to a double-spending attack in a fast payment setting in Bitcoin. The attack can only work when merchants operate on any client version prior to 0.8.2. Our aim is therefore to raise the awareness of merchants to adopt version 0.8.2 (or 0.8.3) if they are willing to accept fast payments [1].