Oana-Mădălina Ciobotaru, Dominique Unruh, Michael Backes
Long-term security ensures that a protocol remains secure even in the future, when the adversarial computational power could, potentially, become unlimited. The notion of universal composability preserves the security of a cryptographic protocol when it is used in combination with any other protocols, in possibly complex systems. The area of long-term universally composable secure protocols has been developed mostly by Müller-Quade and Unruh. Their research conducted so far has shown the existence of secure long-term UC commitments under general cryptographic assumptions, thus without having an emphasis on the efficiency of the protocols designed. Building on their work and using very efficient zero-knowledge proofs of knowledge from [CL02], this thesis presents a new long-term universally composable secure commitment protocol that is both efficient and plausible to use in practice.
Today's mobile devices have characteristic of random mobility in the heterogeneous networks. Thus they should have various kinds of security requirements. To satisfy these requirements, there are many researches on security and authentication for mobile devices. TCG(Trusted Computing Group) designed TPM(Trusted Platform Module) for providing privacy and authentication to users. Also TCG suggest a protocol, called DAA(Direct Anonymous Attestation) which uses zero knowledge proof theory. In this paper, we will implement DAA protocol using Java and show the efficiency and the problems in the DAA protocol. Finally, we will suggest an efficient mobile DAA model through Java test module for the DAA protocol.
The Czech Republic and Slovakia, like other transition countries in Central and Eastern Europe, have given significant lip service to fiscal decentralization and engaged in public administration reforms. But the subnational governments of their public finance systems still lack relative autonomy, which could be addressed partly through developing independent revenue sources for their municipalities and regions. Currently, such independent revenue sources include the proceeds of a strictly nominal property tax as well as those of a small set of local user fees and taxes designed and approved by the central governments. Together they represent only about 5 percent of total municipal budget revenues.
Fei Yuan, Ran Tao, Zhigang Xu, Mingxing Liu · 6 authors
Based on the theoretical literature of fiscal decentralization, we discuss the political economy of inter-governmental fiscal arrangements in China and examine how a transfer-based decentralization impacts on local public employment. A theoretical model is built to show that compared to their counterparts in better-endowed localities, local governments in worse-endowed localities that are more heavily dependent on upper level fiscal transfers to finance their spending have higher incentives to increase public employment to build local political support rather than invest in growth-promoting public goods. Using a county-level panel data set from 1994 to 2003, we empirically identify the causality from higher transfer dependency to the expansion of public employment with an instrumental variable approach. It is argued that under a governance regime in which local governments are more accountable to the upper level than to local constituency, transfer-based decentralization, either through general-purpose transfer or through earmarked transfer, would both lead to serious problems. The policy implication is that expenditure decentralization needs to be accompanied by both revenue and political decentralization to achieve better local governance outcomes.
A non-interactive zero-knowledge proof protocol based on Elliptic Curve Encryption was proposed,and based this protocol,a publicly verified secret sharing scheme was proposed too.In the scheme,secret and secret shadow were embedded onto the points of Elliptic Curve,anybody can verify them publicly,and only the legitimate participants set can recover the secret key,but knowing nothing about the secret key.This scheme can prevent adversaries from getting the secret,the dealer from distributing improper data and the participants from cheating each other efficiently.Furthermore, it is propitious for the replication and update of secret.
① Based on technologies of binary tree,bit commitment and zero knowledge proof,a fair and unlinkable divisible electronic cash scheme is which do not need the trusted third party was proposed.The complexity both of open account and withdraw protocol is O(N+K).The complexity of spending any node is proportional to poly(K) polylog(N).And the complexity of deposit protocol is the same with the payment protocol.The security of the scheme is based on the assumptions of strong RSA problems,the hardness of calculating discrete logarithm and the existence of the one-way hash function.
Based on a random survey for 50 school districts in 20 counties of western China,this pa- per empirically measures and discusses the allocation of personnel power in rural education system. By examining the characteristics of personnel administration system,we discover that the impacts of education finance reform on the reallocation of personnel power.The personnel power in the educa- tion system has been centralized to county education bureau and party organization bureau in most of sample school districts,while the township government gradually loses the control during the educa- tion finance reform.Only in a small number of districts,the decentralized system for personnel ad- ministration can be established.
The thesis deals with problems facing municipal financing in Azerbaijan. Following the exploration of the options for a better design of local government financing.
ABSTRACT\nA students’ Loan scheme is one among many alternatives for financing higher education in various countries around the world. Tanzania is one of the countries that have been practicing loan scheme system for financing higher education sub-sector. The purpose of this study is to examine the performance of the students’ loan scheme in Tanzania basing on the views of the stakeholders, mostly higher education students who are the main beneficiaries of the scheme.\n\nSome university students at the University of Dar es Salaam, the policy makers and policy implementers in the Ministry of Higher Education, Science and Technology and the Higher Education Student Loan Board respectively, were identified for the study. The study was guided by two research questions. These are: what is the performance of higher education student loan scheme in terms of the procedures for loan application and money disbursement; and does the student loan scheme contain the structures for loan recovery to the extent of being able to recover the loan?\n\nA qualitative strategy has been used in this study. Multiple methods were used for data collection, namely semi-structured interview, group discussion and documentary analysis. Twelve students of different academic years of study and student leaders at the student organization level, two policy makers and two policy implementers were interviewed. Twenty students were involved in a focused group discussion. And various documents including policy documents, guidelines and website documents were analyzed. Data collected was analyzed by induction process.\n\nThe findings show that the loan scheme in Tanzania is partly not performing well in terms of application procedures, disbursement of funds to students and loan recovery. Therefore to make the loan scheme perform at the convenience of the stakeholders, it is recommended that the government should decentralize the HESLB to district level (establish the district offices). By doing so some services such as distribution and collection of loan application forms and means-testing can be done at the district offices. In addition, it is recommended that the loan application forms can also be stationed at Advanced Secondary Schools to make it easy for the applicants to access them as most of the applicants are students from these schools.
Viktória Vásáry, Andrea Elekes, Péter Halmai, Vasary, Viktoria · 6 authors
Can we agree fully with the statement, that “agricultural spending is a major distorting factor in the EU economy and a distinct obstacle to the Lisbon agenda’s implementation”? (Gros, 2008) Is it without question that Europe’s agriculture is in position to become sustainable and competitive without certain kind of common policy with no Community financing? Is it unambiguous in every respect, that the challenges facing the sector – globalization, trade liberalization, climate change, water management, Lisbon process, enlargement, changing preferences – could be answered at national level utilizing exclusively national financial sources? The answers to these questions are complex. So the purpose of the paper is multiple: - Exploration of factors justifying community level intervention. – Could be applied the bottom line of the “decentralization theorem” to budgetary questions and needs of the agricultural policy? According to our hypothesis the answer is considered yes. - Assessing present CAP - taking into account its ability to provide EU wide public goods (multifunctional elements serve in deed significant cross-border externalities) and to create EU value added. - Making an attempt to redefine EU’s agricultural policy through exploring objectives having a greater impact by being implemented at the supranational level and not at other secondary decision levels. – Making an attempt to outline a Common Rural Policy, a policy promoting the provision of public goods required by the society by means of targeted and decoupled economic policy measures. In order to attain the objectives of the paper we apply the theory of fiscal federalism, make analysis on EU public finances in a broader context.
The private multi-party computation protocol proposed by Claude Crepeau etc.is not only complicated but very inefficient.This paper describes a new protocol with an efficient global commitment transfer sub-protocol.With a first two round string oblivious transfer,the protocol can avoid performing a large mount of bit oblivious transfers.And with bit commitment with XOR,zero knowledge proofs are very easy.This PMPC protocol is conceptually simple and more efficient.The security and complexity of the protocol are also discussed in this paper.
This article focuses on a kind of MP2P(Mobile P2P)network,a hybrid architecture,based on mobile computing,where the mobile terminals with Ad Hoc connections can communicate with each other via the P2P technology.The paper mainly makes a study on the secure communication in the mobile P2P network,with One-Round Zero-Knowledge Proofs for the identity authentication.Also the relative performances and efficiency of the system are discussed.
Chinese Higher Education Institutions(HEis) have witnessed great changes after imple- menting the open-door policy for about 30 years.This paper discusses the eight changes of HEIs re- form as follows:1)The unitary state-owned/state-run system has changed into one financed and run by various social sectors such as business enterprises,individuals,and other social stakeholders; 2)The governance of HEIs has changed from centrally-governed to a co-governed mode by central and provincial governments;3) The highly centralized administration system had been decentralized so that HEIs had more autonomy in school management;4) HEIs'funding system shifted from total- ly government-paid to fund-raising from multiple avenues;5)The knowledp-delivery model was transformed from knowledge-orientated and teaching-centered to learner-centered and learning- based;6)Admission and placement system are intending to face the market and cater to market needs;7) HEIs are tring to promote internationalization,rather than focusing only on providing ed- ucation domestically;8) HEIs has also changed the self-served logistic system,actively inviting so- cial stakeholder to provide logistical services for students and faculty.
Protecting software integrity is a key to successfully maintain its own credibility and reduce the financial and technical risks caused from a lack of integrity. Although researchers have been putting effort on improving software development techniques and preventing human errors during the software development process, it is still a daunting task to make non-vulnerable software in practice. For example, the national vulnerability database shows that a set of new software vulnerabilities are discovered every day.
Since developing non-vulnerable software is hardly achievable, in this research, we look for a way to achieve software integrity while they are used. In particular, this dissertation investigates three mechanisms to protect software integrity at runtime. Firstly, this dissertation presents a protection mechanism that can thwart attacks that try to exploit memory corruption vulnerabilities of software. The protection mechanism is provided by randomizing the program's runtime memory address layout and the memory objects. As a result, it hinders memory corruption attacks by preventing an attacker being able to easily predict their target addresses. The protection mechanism is implemented by a novel binary rewriting tool that can randomly place the code and data segments of programs and perform fine-grained permutation of function bodies in the code segment as well as global variables in the data segment. Our evaluation results show minimal performance overhead with orders of magnitude improvement in randomness.
Secondly, this dissertation investigates a vulnerability identification mechanism named as CBones that can discover how unknown vulnerabilities in C programs are exploited by verifying program structural constraints. CBones automatically extracts a set of program structural constraints via binary analysis of the compiled program executable. CBone then verifies these constraints while it monitors the program execution to detect and isolate the security bugs. Our evaluation with real-world applications that known to have vulnerabilities shows that CBones can discover all integrity vulnerabilities with no false alarms, pinpoint the corrupting instructions, and provide information to facilitate the understanding of how an attack exploits a security bug.
Lastly, this dissertation identifies the need of dynamic attestation to overcome the limitations of existing remote attestation approaches. To the best of our knowledge, we are the first to introduce the notion of dynamic attestation and propose use of dynamic system properties to provide the integrity proof of a running system. To validate our idea, we develop an application-level dynamic attestation system named as ReDAS (Remote Dynamic Attestation System) that can verify runtime integrity of software. ReDAS provides the integrity evidence of runtime applications by checking their dynamic properties: structural integrity and global data integrity. These properties are collected from each application, representing the application's unique runtime behavior that must be satisfied at runtime. ReDAS also uses hardware support provided by TPM to protect the integrity evidence from potential attacks. Our evaluation with real-world applications shows that ReDAS is effective in capturing runtime integrity violations with zero false alarms, and demonstrates that ReDAS incurs 8% overhead on average while performing integrity measurements.
Pelaksanaan desentralisasi fiskal di Indonesia dilakukan sebagai salah satu langkah dalam memberikan otonomi yang lebih luas, nyata dan bertanggungjawab kepada pemerintah daerah. Penerapan desentralisasi dalam bentuk perimbangan keuangan ini diharapkan mampu mewujudkan kemandirian daerah terutama dalam bidang penerimaan dan pengeluaran. Tujuan penelitian ini adalah untuk menyelidiki pengaruh komponen-komponen desentralisasi fiskal yaitu dana perimbangan, lain-lain pendapatan terhadap pendapatan asli daerah dan pengaruh dana perimbangan, lain-lain pendapatan dan pendapatan asli daerah terhadap belanja pembangunan. Penelitian ini menggunakan data sekunder berupa realisasi APBD yaitu dana perimbangan, lain-lain pendapatan, pendapatan asli daerah dan belanja pembangunan dari kabupaten/kota yang ada di lingkup Propinsi Bali. Pertimbangannya adalah karena kabupaten/kota yang ada di lingkup Propinsi Bali memiliki sumber daya alam yang terbatas jika dibandingkan dengan daerah lain. Keterbatasan ini memaksa kabupaten/kota di lingkup propinsi Bali untuk menggali sumber pendapatan asli daerahnya yang akan digunakan untuk membiayai belanja daerahnya agar pelayanan publik tetap dapat dilakukan secara optimal. Sumber data utama berasal dari Departemen Keuangan, Badan Pemeriksa Keuangan dan publikasi Biro Pusat Statistik. Teknik analisis yang digunakan adalah statistik deskriptif dan regresi model panel dengan metode fixed effect. Sebagai hasilnya penelitian ini berhasil mendukung adanya pengaruh positif pelaksanaan desentralisasi fiskal melalui komponen dana perimbangan terhadap pendapatan asli daerah tetapi tidak dengan komponen lain-lain pendapatan. Terhadap belanja pembangunan hanya komponen pendapatan asli daerah yang berpengaruh positif terhadap belanja pembangunan, sementara dana perimbangan dan lain-lain pendapatan tidak. Hal ini menunjukkan bahwa masih terdapat ketergantungan sumber penerimaan dari pemerintah pusat melalui dana perimbangan untuk kabupaten/kota yang ada di lingkup propinsi Bali.
Implementation of fiscal decentralization in Indonesia has been done as one way to give wider real and responsible autonomy to local government. Application of decentralization in form of financial balance is expected to be able to realize local autonomy, particularly in income and expenditure sides. The objective of this research was to investigate influence of fiscal decentralization components, including transfers and other revenues on own revenues and influence of transfers, other revenues and own revenues on development expenditures. This research used secondary data of the realized regional budget consisting of transfers, other revenues, own revenues and development expenditures that was obtained from regencies/municipalities in Bali Province. The selection is based on consideration that regencies/municipalities in Bali Province have limited natural resources compared with other regions. The limitation force regencies/municipalities in Bali Province to explore source of actual regional balance that will be used to finance its local expenditure in order to keep public service run optimally. The main data source was from Ministry of Finance, the Supreme Audit Agency and publications of the Central Bureau of Statistics. It used descriptive statistic analysis and panel model regression with fixed effect method. Results of the research supported positive influence of implementation of fiscal decentralization through component of transfers on own revenues but not with other revenues component. For development expenditure, only own revenues has positive influence on development expenditure, while transfers and other revenues has not. It indicated that there was dependence on receipt from central government through transfers in regencies/municipalities in Bali Province.
Synopsis: Concern over emissions and climate change has led over half of the states to enact portfolio (RPS) legislation requiring regulated electric utilities to obtain some fraction of their power requirements from sources defined as Legislation to institute a federal RPS may follow. In reality, RPS is a policy in search of a rationale, at odds with principles of efficient environmental regulation and poorly suited to promote other policies favored by its supporters. The actual record of state implementations has been largely symbolic. Very few states with binding RPS requirements are currently in compliance with their own programs, and a federal RPS will be subject to the same forces that have led to state-level failure. The recent history of renewables leads to a conclusion that existing and proposed mandates are better viewed as special interest legislation than as rational responses to climate change and fossil-fuel power plant emissions. I. INTRODUCTION Electricity from renewable sources is fast becoming a multipurpose remedy that will alleviate energy scarcities, abate air pollution, and mitigate climate change. As of July 2007, over half of the states had enacted portfolio standards (RPS) requiring electric utilities to obtain portions of their power from sources legislatively defined as renewable. ' On August 4, 2007, the U.S. House of Representatives voted in favor of a national RPS, but the Senate failed to pass a comparable provision.2 Supporters of a national RPS have long viewed it as an environmental measure that can also slow the accumulation of greenhouse gases (GHG).3 They have more recently argued that it is, among others, an industrial policy to manufacturing jobs and declining regions, a market intervention that could lower energy prices, a stimulus to development of new technologies, an instrument for risk management, a trade policy initiative, and a weapon in the war on terrorism.4 In reality, a national RPS is singularly ill-suited for any of these tasks. It will be an inefficient and inequitable environmental policy that reduces emissions at higher cost than necessary and is largely incompatible with existing air quality regulations. Some of the non-environmental rationales are elementary economic fallacies and others are at best conjectures. Worse yet, the record of state-level RPS compliance and enforcement strongly suggests that the effects of a federal program will be either minimal or perverse. Psychologically and politically satisfying, a national RPS is likely to obstruct the development of efficient policies. The range of public figures and distinguished commissions favoring a national RPS may indicate no more than an expectation that it will provide a new forum for interest-group politics.5 We begin with data on renewables which suggests that a federal RPS will bring little diversity in generation resources and few environmental benefits. The next sections examine advocates' claims for it, finding them inadequate at best. As environmental policy, an RPS is inefficient by every economic standard. It is a costly measure whose effects on emissions are uncertain, difficult to integrate with existing environmental regulation, and needlessly disruptive of generation investments intended to comply with anticipated emissions rules. Other purported consequences are also questionable. As macroeconomic or industrial policy, a national RPS cannot possibly create net increases in employment and rural areas that it will revitalize seldom need the help. Claims that it is necessary to stimulate reductions in production cost lose their force in a global economy, as do expectations that it will position the U.S. to dominate the world renewables market. Rather than facilitating risk management, standard renewables contracts only transfer it from utilities to captive customers. National security is better advanced through direct policies instead of compulsory investment in renewables. …
This thesis is concerned with stochastic perturbation theory of the symmetric eigen-value problem. In particular, we provide results about the probability of interchanges in the ordering of the eigenvalues and changes in the eigenvectors of symmetric matrices subject to stochastic perturbations. In this analysis we use a novel combination of traditional Numerical Linear Algebra, Perturbation Theory and Probability Theory. The motivation for this study arises from reliability of spectral clustering of networks, when network data is subject to noise. As far as we are aware, there is nothing comparable in the literature. Further, we make conjectures from which we derive an asymptotic relation between the distributions of the largest eigenvalue and the 2-norm of random symmetric ma- trices, whose entries above the main diagonal are independent, identically distributed random variables with probability density functions being symmetric with respect to zero, including matrices from the Gaussian Orthogonal Ensemble (GOE). As far as we know, some of these conjectures are not new (possibly only as conjectures) but we are not aware of any proofs. Also, we consider networks of coupled oscillators. In their analysis we use both, knowledge of dynamical systems and spectral properties of non-negative matrices. As a result, we present an algorithm, which uncovers the \\master-slave" structure of the network. With its help, the analysis of the dynamics and the entrainment of the entire network can be reduced to considering only few of the oscillators, those whose dynamics determine the behaviour of the rest. This can be helpful in large networks exhibiting the \\master-slave" structure. Finally, we consider similarities of spectral clustering with respect to di®erent matrices which can be associated with a given network. In particular, we compare clustering of products of Path graphs with respect to two di®erent matrices: the Laplacian and the Normalised Laplacian matrices of the graph. We make the comparison by constructing a Homotopy between two eigenvalue problems and, using some Linear Algebra techniques, we show that the two matrices give similar spectral clusterings when applied to products of Path graphs.
In financing process,the multinational company faced a lot of risks,especially,the political risk.So we need consider politi-cal risk brought by domestic political system like local companies and the difference between policies from different countries due to its own particularity.We can make reasonable subjective judgment to political risk by the predicator's knowledge and experience to take precautionary and decentralized strategy to decrease financing risk.
Public-key cryptography is a key technology for making the Internet and other IT infrastructures secure. The security of the established public-key cryptosystems relies on the difficulty of factoring large composite integers or computing discrete logarithms. However, it is unclear whether these computational problems remain intractable in the future. For example, Shor showed in 1994 that quantum computers can be used to factor integers and to compute discrete logarithms in polynomial time. It is therefore necessary to develop alternative public-key cryptosystems which do not rely on the difficulty of factoring or computing discrete logarithms and which are secure even against quantum computer attacks. We call such cryptosystems quantum-immune. To prove the security of these quantum-immune cryptosystems, appropriate security models have to be used. Since quantum computers are able to solve problems in polynomial time which are supposed to be intractable for classical computers, the existing security models are inadequate in the presence of quantum adversaries. Therefore, new security models have to be developed to capture quantum adversaries. Properties of these new security models have to be investigated. On a more practical level, the quantum-immune cryptosystems have to be implemented in a way that they can seamlessly replace established cryptosystems. The implementations have to be efficient and suitable for resource-constrained devices. They must easily integrate into existing public-key infrastructures. This thesis contributes to both the theory and practice of quantum-immune cryptography, addressing the above-mentioned challenges. In the theoretical part, we concentrate on the quantum zero-knowledge property of interactive proof systems. We show for the first time that the quantum statistical, perfect, and computational zero-knowledge properties are preserved under sequential composition of interactive proof systems. In the practical part, we provide implementations of the most important quantum-immune cryptosystems. We present efficiency improvements of some of the alternative cryptosystems. The implementations are very efficient and easily integrate into existing public-key infrastructures. We present comprehensive timings that show that the alternative cryptosystems are competitive or even superior compared to established cryptosystems. Finally, we present a new cryptographic API that is particularly well-suited for resource-constrained devices like mobile phones and PDAs. With this API, the alternative cryptosystems can also be used with these devices.
Traditional definition of signature of knowledge can not prevent steganographic communication.To solve this problem,we introduce and formally define the notion of fairness of the signature of knowledge.We then construct a fair signature of knowledge scheme by use of fair zero-knowledge proofs of knowledge,and finally prove that this scheme indeed guarantees the fairness and can efficiently prevent steganographic communication.
Cryptography and Data Security
Privacy-Preserving Technologies in Data
Advanced Steganography and Watermarking Techniques
Microfinance opportunities have been successfully expanding in Ethiopia during the past fifteen years, including in remote villages, where the majority of people are engaged in smallscale agriculture, which is little supported by modern technology. Some of the key strategies for the success include: innovative adaptation of the group guarantee lending model, successfully customized to local Ethiopian realities; decentralization of operation, including a focus on using indigenous knowledge and resources in client screening and follow-up; appropriate strategies to deal with financing small scale (rain-fed) agriculture, often subject to season changes. However, much remains to be done. The outreach in micro-credit is estimated to have satisfied only a small proportion of the potential demand, while the growth of individual enterprises and the impact on clients' income remain low. It is becoming more and more challenging to further expand the micro-credit outreach, introduce inclusive finance to reach remote villages and very poor people, as well as ensure an impact on the lifestyle of clients. This is due, among other things, to poor infrastructure, particularly the road network and other communication channels, low level business support, as well as the 'entrepreneurship challenge'. This calls for a collaborative effort of all stakeholders in rural development. The present paper examines the opportunities and challenges faced while expanding access to microfinance to poor people in remote areas.