Lu Li, Jinsong Han, Lei Hu, Jinpeng Huai · 6 authors
Most of the current trust models in peer-to-peer (P2P) systems are identity based, which means that in order for one peer to trust another, it needs to know the other peer's identity. Hence, there exists an inherent tradeoff between trust and anonymity. To the best of our knowledge, there is currently no P2P protocol that provides complete mutual anonymity as well as authentication and trust management. We propose a zero-knowledge authentication scheme called pseudo trust (PT), where each peer, instead of using its real identity, generates an unforgeable and verifiable pseudonym using a one-way hash function. A novel authentication scheme based on zero-knowledge proof is designed so peers can be authenticated without leaking any sensitive information. With the help of PT, most existing identity-based trust management schemes become applicable in mutual anonymous P2P systems. We analyze the levels of security and anonymity in PT, and evaluate its performance using trace-driven simulations and a prototype implementation. The strengths of pseudo trust include the lack of need for a centralized trusted party or CA, high scalability and security, low traffic and cryptography processing overheads, and man-in-middle attack resistance. We aim for the pseudo trust design to be included in the P2P trust and anonymity context.
Contents: Foreword Preface The Philippine Regions, 1987 The Philippine Regions, 2003 1. The Philippines and Regional Development Hal Hill, Arsenio M. Balisacan and Sharon Faye A. Piza PART I: EAST ASIA AND BEYOND 2. Globalization, Geography and Regional Policy John Weiss 3. Regional Development: Analytical and Policy Issues Hal Hill 4. The East Asian Experience: The People's Republic of China Ligang Song 5. The East Asian Experience: Indonesia Budy P. Resosudarmo and Yogi Vidyattama PART II: THE PHILIPPINES 6. Local Politics and Local Economy Emmanuel S. de Dios 7. The Quality of Local Governance and Development under Decentralization Joseph J. Capuno 8. Regional Labour Markets and Economic Development in the Philippines Emmanuel F. Esguerra and Chris Manning 9. Decentralization and the Financing of Regional Development Rosario G. Manasan 10. Infrastructure and Regional Growth Gilberto M. Llanto 11. Development of the Rural Non-farm Sector in the Philippines and Lessons from the East Asian Experience Jonna P. Estudillo, Tetsushi Sonobe and Keijiro Otsuka 12. Regional Responses to Trade Liberalization and Economic Decentralization Gwendolyn R. Tecson 13. Local Growth and Poverty Reduction Arsenio M. Balisacan References Index
Abstract : Open source software development (OSSD) is a community-oriented, network-centric approach to building complex software systems. OSSD projects are typically organized as edge organizations that lack an explicit management regime to control and coordinate decentralized project work. However, a growing number of OSSD projects are developing, delivering, and supporting large-scale software systems that are displacing proprietary software alternatives. The U.S. Department of Defense is now committed to the adoption and deployment of software-intensive systems with open architectures and OSS components for application areas including command and control systems. Recent empirical studies of OSSD projects reveal that OSS developers often self-organize into organizational forms we characterize as evolving socio-technical interaction networks (STINs). These STINs emerge in ways that effectively control semi-autonomous OSS developers and coordinate project activities to produce reliable and adaptive software systems. In this paper, we examine how practices and processes enable and govern edge organizations like OSSD projects when coalesced and configured as contingent, sociotechnical interaction networks. In so doing, we draw on results from two ongoing case studies of governance activities and elements in a small and a large OSSD project.
We present two universally composable and practical protocols by which a dealer can, verifiably and non-interactively, secret-share an integer among a set of players. Moreover, at small extra cost and using a distributed verifier proof, it can be shown in zero-knowledge that three shared integers a, b, c satisfy ab = c. This implies by known reductions non-interactive zero-knowledge proofs that a shared integer is in a given interval, or that one secret integer is larger than another. Such primitives are useful, e.g., for supplying inputs to a multiparty computation protocol, such as an auction or an election. The protocols use various set-up assumptions, but do not require the random oracle model.
Abstract. We show an efficient secure two-party protocol, based on Yao’s construction, which provides security against malicious adversaries. Yao’s original protocol is only secure in the presence of semi-honest adversaries. Security against malicious adversaries can be obtained by applying the compiler of Goldreich, Micali and Wigderson (the “GMW compiler”). However, this approach does not seem to be very practical as it requires using generic zero-knowledge proofs. Our construction is based on applying cut-and-choose techniques to the original circuit and inputs. Security is proved according to the ideal/real simulation paradigm, and the proof is in the standard model (with no random oracle model or common reference string assumptions). The resulting protocol is computationally efficient: the only usage of asymmetric cryptography is for running O(1) oblivious transfers for each input bit (or for each bit of a statistical security parameter, whichever is larger). Our protocol combines techniques from folklore (like cut-and-choose) along with new techniques for efficiently proving consistency of inputs. We remark that a naive implementation of the cut-and-choose technique with Yao’s protocol does not yield a secure protocol. This is the first paper to show how to properly implement these techniques, and to provide a full proof of security. Our protocol can also be interpreted as a constant-round black-box reduction of secure two-party com-putation to oblivious transfer and perfectly-hiding commitments, or a black-box reduction of secure two-party computation to oblivious transfer alone, with a number of rounds which is linear in a sta-tistical security parameter. These two reductions are comparable to Kilian’s reduction, which uses OT alone but incurs a number of rounds which is linear in the depth of the circuit [18]. 1
The use of quantum correlations to attack security protocols is an important research line deserving growing attention. An important class of cryptographic protocols used as building blocks for several other more complex protocols is zero-knowledge proof systems. One of the properties that zero-knowledge proof systems are assumed to satisfy is that it is impossible for the verifier to show to a third party that he has interacted with the prover (impossibility of transferring proofs). Herein, it is shown how Bell pairs, together with tamper-proofing, can be used to break the impossibility of transferring proofs for an important class of zero-knowledge proof systems.
A zero-knowledge proof(ZKP) is a powerful tool which can be used and already be used for many cryptographic applications.But for the completeness property and the soundness property the existing zero-knowledge proofs are iterative in nature.The multiple communication rounds makes ZKPs unsuitable in practice.In this thesis,propose a new ZKP protocol which runs in one-round while ensure the completeness property and the soundness property.On the other hand,extend ZKPs to elliptic curves.At last,proposed a necessary condition which was needed by constructing a one-round zero-knowledge proofs protocol.
Zero-knowledge proof (ZKP) based authentication protocols provide a smart way to prove an identity of a node without giving away any information about the secret of that identity. There are many advantages as well as disadvantages to using this protocol over other authentication schemes, and challenges to overcome in order to make it practical for general use. This chapter examines the viability of ZKPs for use in authentication protocols in networks. It is concluded that nodes in a network can achieve a desired level of security by trading off key size, interactivity, and other parameters of the authentication protocol. This chapter also provides data analysis that can be useful in determining expected authentication times based on device capabilities. Pseudocode is provided for implementing a graph-based ZKP on small or limited processing devices.Request access from your librarian to read this chapter's full text.
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Cryptography and Data Security
Privacy-Preserving Technologies in Data
Physical Unclonable Functions (PUFs) and Hardware Security
Computational grids enable the sharing, aggregation, and selection of (geographically distributed) computational resources and can be used for solving large scale and data intensive computing applications. Computational grids are an appealing target application for market-based resource allocation especially given the attention in recent years to “virtual organizations ” and policy requirements. In this paper, we present a framework for truthful, decentralized, dynamic auctions in computational grids. Rather than a fullyspecified auction, we propose an open, extensible framework that is sufficient to promote simple, truthful bidding by endusers while supporting distributed and autonomous control by resource owners. Our auction framework incorporates resource prediction in enabling an expressive language for end-users, and highlights the role of infrastructure in enforcing rules that balance the goal of simplicity for end users with autonomy for resource owners. The technical analysis leverages simplifying assumptions of “uniform failure” and “threshold-reliability” beliefs.
We introduce a new notion called `-isolated proofs of knowledge (`-IPoK). These are proofs of knowledge where a cheating prover is allowed to exchange up to ` bits of communication with some external adversarial environment during the run of the proof. Without any additional setup assumptions, no witness hiding protocol can be an `-IPoK for unbounded values of `. However, for any pre-defined threshold `, and any relation in NP and we construct an `-IPoK protocol for that relation. The resulting protocols are zero knowledge (ZK) in the standard sense, i.e., w.r.t. a verifier that communicates only with the prover during the proof. The cost of having a large threshold ` is a large communication complexity of the constructed protocol. We analyze these costs and present a solution that is asymptotically optimal. If a cheating verifier is allowed to communicate arbitrarily with an external environment, it is not possible to construct an `-IPoK that is also ZK with respect to such a verifier. As another new notion, we define `-isolated zero knowledge (`-IZK) where the verifier is `-isolated. For every relation in NP and every `, we construct an `-IPoK protocol that is also `-IZK. We describe several applications of `-IPoK protocols under the physical assumption that one can `isolate a prover for the duration of the proof phase. Firstly, we can use a witness indistinguishable (WI) `-IPoK to prevent “man-in-the-middle” attacks on identification schemes. Prior results for this scenario required all verifiers to register keys under a PKI, or the ability to fully isolate the prover. Secondly, a partially isolated prover can register a public key and use a WI `-IPoK to prove knowledge of the corresponding secret key to another party acting as a verifier. This allows us to set up a PKI where the key registrant does not need to trust the Certificate Authority. The PKI is not perfect since the proof is only witness indistinguishable and not zero knowledge. In a companion paper, we show how to set up such a PKI and use it to implement arbitrary multiparty computation securely in the UC framework without relying on any trusted third parties.
The traditional theory of public finance has made a strong case for a major role for fiscal decentralization. This case is based on an improved allocation of resources in the public sector. And it has four basic elements. First, regional or local governments are in a position to adapt outputs of public services to the preferences and particular circumstances of their constituencies, as compared to a central solution which presumes that one size fits all. Second, in a setting of mobile households, individuals can seek out jurisdictions that provide outputs well suited to their tastes, thereby increasing the potential gains from the decentralized provision of public services (Tiebout 1956). Third, in contrast to the monopolist position of the central government, decentralized levels of government face competition from their neighbors; such competition constrains budgetary growth and provides pressures for the efficient provision of public services. And fourth, decentralization may encourage experimentation and innovation as individual jurisdictions are free to adopt new approaches to public policy; in this way, decentralization can provide a valuable Alaboratory for fiscal experiments. However, this basic economic rationale for decentralization of the public sector is not quite so simple and compelling as it appears. Some of the more recent literature provides, first, a thoughtful and provocative critique of the traditional view of fiscal decentralization, and, second, some new approaches that reveal its dark side, especially in practice. There is emerging, in short, a broader perspective on fiscal decentralization that raises some serious questions about its capacity to provide an unambiguously positive contribution to an improved performance of the public sector. My purpose in this paper is twofold. First, I want to review the basic theory of fiscal decentralization. There are some loose ends to the traditional argument that open up some intriguing issues. Second, I want to turn to some of new literature on fiscal discipline in multilevel government. This literature has focused attention on some basic and destructive forces that can undermine the economic performance of a relatively decentralized public sector. I find it helpful to begin by revisiting a Decentralization Theorem that I formulated long ago. As a point of departure, I want to explain briefly why I introduced the proposition and the rationale for its particular form and proof.
In this paper, we analyze a class of models in which there are interjurisdictional spillovers among heterogeneous jurisdictions, as illustrated for instance by CO2 emissions that affect the global environment. Each jurisdiction's emissions depend upon the local stock of private capital. Capital is interjurisdictionally - mobile and may be taxed to help finance local public expenditures. We show that decentralized policymaking leads to efficient resource allocations in important cases, even in the complete absence of corrective interventions by higher - level governments or coordination of policy through Coasian bargaining. In particular, even when the preferences and production technologies differ among the agents, the decentralized system can still result in globally efficient allocation.
Administrative Decentralization seeks to redistribute authority, responsibility and financial resources for providing public services among different levels of government. Administrative Decentralization is the transfer of responsibility for the planning, financing and managing of certain public functions from the central government and its agencies to field units of government agencies. This paper will search for a common theoretical framework of decentralization, then analyzes and assesses the initiatives for decentralization of administration that have been constructed after the emergence of Bangladesh. The major issues and problems of implementation of the decentralization policies in Bangladesh are also discussed suggesting policy measures. This paper is analytical in nature.
The current system of fiscal decentralization in China has a number of serious problems. Whereas it has clearly assigned revenues between the central government and provincial governments, the current system does not provide clear expenditure assignments for almost all levels of governments. In practice, the widely unfunded responsibilities have been taken up by local governments, in particular, by the governments at and under county level. Since 1994, the responsibilities for these local governments have continued to expand. On the other hand, the “tax sharing reform” of 1994 led to a very limited tax bases for local governments. In fact, a significant amount of local governments in China face serious fiscal crisis. First, the vertical and horizontal fiscal gaps are significant in China. The revenue assignments are highly centralized, however the expenditures are highly decentralized. In 2003, major taxes and 54.6% of total tax revenues belonged to the central government, but local government expenditures accounted for 69.9% of total government expenditures. Furthermore, total provincial own revenues only financed 57% of provincial expenditure.
This being the case, the local authorities must do far more than in the past to face up to the challenge of making efficient use of their own assets and external financing for local economic development with a view to reducing poverty; they are also repeatedly urged to practise democracy and development on specific projects by eliciting democratic decisions on the use of the scarce resources provided by themselves and obtained from external sources. Both having constantly to deal with the hard realities of development financing constraints democratically and implementing majority decisions on development in a decentralized structure governed by the subsidiarity principle probably form the ideal course for future poverty-oriented development. Following this course successfully will undoubtedly require staying power of all concerned, both in the partner countries and in the international development cooperation community.
When the case is put here for the decentralization of government, it should be remembered that this approach has not only assumed considerable importance in theory and practice throughout the world, but is also repeatedly adopted for specific areas of development policy. In some newly industrializing countries too there has already been a change of direction, with major strides being taken towards decentralization (as in Brazil, India, Indonesia and Mexico). A question that has yet to be analysed, on the other hand, is why decentralization has not been consistently and comprehensively sought or achieved for rural development in more than a few instances. Regardless of whether, in the end, a decentralization option in comprehensive or weakened form is pursued (see Chapter 13), it is true to say that realistic problem-solving approaches will be possible only if the following requirements are progressively satisfied in development cooperation: 1 The focusing of government, the business community and society on key areas of development policy, according to whether public tasks or tasks of civil society are concerned; 2 The sequencing of development steps, with clear priorities set; 3 The jettisoning of development cooperation ballast from previous develop- ment decades; 4 The pooling of human and financial resources and the setting of develop- ment policy priorities, combined with new forms of technical support and development financing; and 5 Donor coordination and the creation of opportunities for an international division of labour in development cooperation.
The aim of this work is to evaluate the results of the housing policy that was introduced as from the mid-1990s, during the government of President Fernando Henrique Cardoso.The main directives of this policy were the decentralization of actions, the flexibilization of service relating to demand, the formation of partnerships with civilian society, the creation of new sources of financing and the integration of the housing policy with urban policy.As from 1995 laws were changed and programs and sources of financing were created that were a response to the paralysis in which the Brazilian housing sector had found itself since the disbanding of the National Housing Bank (BNH), in 1986.However, old problems persisted: for example, the setting up of funds for financing housing units for low income classes was never put into practice.The use of non-onerous resources was minimal and as a consequence, the distribution of the constructions, both in terms of where and which income band, did not meet the real needs, a fact that has been clearly pointed out in studies on the Brazilian housing déficit.