Division of responsibility and authority for local government debt is an important part of decentralized public finance management system.It has become a precondition to legitimize local government debt in order to solve the current problems in our country.Legitimizing is to identify not only debt-financing rights,but also debt management responsibilities.Local governments have made some explorations about it in recent years.Central government should grant legal borrowing right to local governments,but the debt amount and its using should be strictly controlled.The uniform management agencies should also be set up in Ministry of Finance and public finance departments at province,city and county.
Constructing a multi-level rural finance system is the hardcore for the new countryside construction.Agriculture insurance has played an irreplaceable role in decentralization and debasing the systematic risks of agriculture finance system.In response to the present absence of agriculture insurance laws and provisions,it's compulsory for China to persist in the correct legislation rule,and gradually consummate agriculture insurance legislation so as to accelerate the promotion of new countryside construction.
Electronic voting systems, chat rooms, and electronic auctions are well-known examples of systems that involve many people interacting at the same time in order to achieve a goal: cast a vote, discuss political ideas, and bid for an item. Yet, some security goals of these multi-party protocols have not been carefully examined as they should. For example, how different is protecting the anonymity of the sender---as in an electronic election---versus protecting the anonymity of both the sender and the receiver---as in a political chat room? Or, can online surveys guarantee that participants do not influence each other's answers? This dissertation studies two of these properties: anonymity and independence of inputs.
We first revisit the problem of anonymous communication, in which users wish to send messages to each other without revealing their identities. We propose a novel framework to organize and compare anonymity definitions. In this framework, we present simple and practical definitions for anonymous channels in the context of computational indistinguishability. The notions capture the intuitive properties of several known types of anonymous channels, and also model practical scenarios where information is leaked in the system. We also compare these notions showing how stronger notions can be built from weaker ones in a provably optimal way. With these tools, we revisit the security of previous popular anonymous channels protocols.
In applications where multiple senders can broadcast messages at the same time (like electronic auctions or elections), it is often important to enforce the simultaneous transmission of messages, so that no sender can decide its broadcast message based on the values broadcast by other players. In the second part of the dissertation, we study the definitions of independence (or Simultaneous Broadcast) proposed in the literature, obtaining a full characterization of their applicability and relative strength. In particular, we show that the latest definition, under which the most (round) efficient solution was proven secure, is strictly weaker than the previous definitions. We thus reopen the problem of either proving the efficient solution satisfies the strongest definition of security or finding an alternative efficient protocol that does so.
We conclude by addressing this last problem. We present a definition of simultaneous broadcast under the Universally Composable framework, and show that this stronger notion can be achieved by a computationally efficient, constant-round construction. Our construction builds on an existent adaptive verifiable secret sharing scheme, and does not resort to generic zero-knowledge proofs or commitment schemes present in previous solutions.
Electronic voting systems, chat rooms, and electronic auctions are well-known examples of systems that involve many people interacting at the same time in order to achieve a goal: cast a vote, discuss political ideas, and bid for an item. Yet, some security goals of these multi- party protocols have not been carefully examined as they should. For example, how different is protecting the anonymity of the sender -- as in an electronic election -- versus protecting the anonymity of both the sender and the receiver -- as in a political chat room? Or, can online surveys guarantee that participants do not influence each other's answers? This dissertation studies two of these properties: anonymity and independence of inputs. We first revisit the problem of anonymous communication, in which users wish to send messages to each other without revealing their identities. We propose a novel framework to organize and compare anonymity definitions. In this framework, we present simple and practical definitions for anonymous channels in the context of computational indistinguishability. The notions capture the intuitive properties of several known types of anonymous channels, and also model practical scenarios where information is leaked in the system. We also compare these notions showing how stronger notions can be built from weaker ones in a provably optimal way. With these tools, we revisit the security of previous popular anonymous channels protocols. In applications where multiple senders can broadcast messages at the same time (like electronic auctions or elections), it is often important to enforce the simultaneous transmission of messages, so that no sender can decide its broadcast message based on the values broadcast by other players. In the second part of the dissertation, we study the definitions of independence (or Simultaneous Broadcast) proposed in the literature, obtaining a full characterization of their applicability and relative strength. In particular, we show that the latest definition, under which the most (round) efficient solution was proven secure, is strictly weaker than the previous definitions. We thus reopen the problem of either proving the efficient solution satisfies the strongest definition of security or finding an alternative efficient protocol that does so. We conclude by addressing this last problem. We present a definition of simultaneous broadcast under the Universally Composable framework, and show that this stronger notion can be achieved by a computationally efficient, constant-round construction. Our construction builds on an existent adaptive verifiable secret sharing scheme, and does not resort to generic zero-knowledge proofs or commitment schemes present in previous solutions
In this paper, a non-interactive zero-knowledge proof scheme is proposed for secure identification in wireless networks, and it uses a timed oblivious transfer technique to enable a single verifier to identify multiple provers. The verifier and the prover do not need to be synchronized in this scheme. This scheme also enjoys the distance bounding property which makes the proposed scheme invulnerable to the relay attack. We propose to use the order statistic for the detection of relay attackers. We show that it is optimal in terms of minimum variance. Finally, we will shed some light on implementation issues of our proposed scheme. I. INTRODUCTION Recent years have witnessed the urgent needs to secure net- works of low power wireless devices as widespread adoption of these devices in our daily life is imminent. Countermeasure of the relay attack has been one of known hard problems for many challenge-response protocols aimed at applications over these networks. The U.S. government backed e-Passport project (cf. US Border Security Act of 2002) requires that the anti-skimming material has to be used to countermeasure the relay attack. Zero-knowledge proof (ZKP) has been used as a fundamen- tal secure primitive for many challenge-response protocols. On ISO/IEC 18092 compatible devices where enhanced pro- cessing capability is normally present, ZKP primitives can be employed to build secure systems. However, the relay attack has been acknowledged as one effective attack to an interactive ZKP (4), (8). Referring to Fig. 1, P, the prover and V , the verifier are both under the control of an adversary, and they are located between the legitimate prover P and verifier V; V identifies itself as a legitimate verifier to P and P identifies itself as a legitimate prover to V. Interaction in ZKP introduces many problems, namely, communication cost, potential protocol vulnerability, etc. One approach to removing the interaction during ZKP is to use offline pre-computation of a series of public keys for a two-party oblivious transfer (OT) protocol (13), (10), (3). Under this approach, the prover uses the OT protocol to send messages to the verifier through multiple rounds; in each round, the prover uses a different OT public key to encrypt the messages. This non-interactive ZKP can enable a single verifier to identify multiple provers as the same OT public key can be used by many provers in a single round (note that the same OT public key should not be used in different rounds). However, the non-interactive ZKP is still vulnerable to relay attack. One practical approach to defending against the relay attack is to associate the absolute location information digitally
This thesis describes an electronic voting system based on Damg\\aa rd, Jurik and Nielsen's generalization of Paillier's probabilistic public key system. A threshold variant of this homomorphic cryptosystem is used to provide universally verifiable elections, where zero-knowledge proofs are used for proving correctness of votes.\n\nUsing this cryptosystem, an electronic voting system that supports voting for 1 out of $L$ candidates is described. Two types of encoding may be used to prove the validity of the votes. The number of proofs needed using normal encoding is linear in $L$, while the number of proofs needed using binary encoding is logarithmic in $L$. It is shown how to extend the system to allow casting a vote for $t$ out of $L$ candidates. This method may easily be used to carry out elections with weighted votes without any added complexity to the system.\n\nThe system is shown to satisfy the requirements for elections at The Norwegian University of Science and Technology (NTNU). A fully functional implementation of the electronic voting system as a distributed system, using Java Remote Method Invocation, is presented. The implementation is used to analyze the feasibility of using this voting system for future elections at NTNU. The implementation is tested using various keylengths and various election parameters. With a keylength of 1024 bits, the simulated time for verification of complex elections is small enough to be considered universally verifiable.
During the reform of fiscal decentralization in our country,local governments turn to relatively independent public sector gradually.In our existing institutional arrangements,as the implicit guarantees taken by central government suffer from the problem of incentive incompatibility,the resulting moral hazards will lead to even higher fiscal risks.On the precaution of moral hazards in local governments,we should set up risk-control mechanism and perfect the existing fiscal system.
Is the
Decentralisation of Water Management for
Agriculture in Vietnam’s Red River Delta a
Break a Break from Tradition?
Decisions taken in the 1980s to establish decentralised local pumping stations
in the Red River Delta continue to influence
the transformation of its water management
system to this day. These technical changes
resulted in the fragmentary decision
making, financing and regulation of water
management in the delta region as a whole.
The current intensification of agriculture in
the Red River Delta has benefited from
these changes, although further decentralisation is limited by the size and the hierarchical organisation of large scale water
management works and by the State’s desire
to maintain its power over the population
through the control of water resources.
Today, cooperatives and hydraulics companies are competing for financial resources,
which creates differences amongst farmers
depending on the availability and price of
water. The State appears to sway on a fine
political line, facing contradictory pressure
from international investors and from internal rivalries within the Vietnamese Communist Party, which rules the country. The
example of the Red River Delta demonstrates that water management is typified by
the fluctuation of its institutions, which are
under constant alteration, as is the society
they stem from.
We propose cryptographic primitives for reading and assigning the (shared) secret found at a secret index in a vector of secrets. The problem can also be solved in constant round with existing general techniques based on arithmetic circuits and the “equality test” in [4]. However the proposed technique requires to exchange less bits. The proposed primitives require a number of rounds that is independent of the size N of the vector, and only depends (linearly) on the number t of computing servers. A previously known primitive for reading a vector at a secret index works only for 2party computations. Our primitives work for any number of computing participants/servers. The proposed techniques are secure against passive attackers, and zero knowledge proofs are provided to show that exactly one index of the array is read/written. The techniques work both with multiparty computations based on secret sharing and with multiparty computations based on threshold homomorphic encryption.
To build a sound fiscal relation among the governments is the goal of the reform of the tax decentralization system. The reform was carried out in 1994, yet a lot of problems have not been solved. In a market-oriented economy, it is a shortcut to construct a sound fiscal relationship among governments by reinspecting the fiscal administrative system of China from the angles of affairs right, property right and transfer payment, and learning the experience from foreign countries.
Traditional design of authenticated key exchange protocol considers communication security, but seldom takes into account the security threat of server compromises. Whenever an authentication server is captured, the intruder can immediately masquerade as legitimate users to successfully log into the system. Although some zero-knowledge-proof methods were designed to relieve this threat, their computation is relatively high due to computationally heavy modular exponentiations employed. A dynamic-verifier based authenticated key exchange protocol is proposed, where the server stores a dynamically changing password-verifier and no password leakage would occur even when the server’s verifier database is stolen. DV-AKE is especially useful for applications where lightweight client is required or lower server computational load is preferred.
Committed oblivious transfer is the natural fusion of one-out-of-two oblivious transfer and bit commitment. Unfortunately, the protocols proposed before are not only complicated but also very inefficient. This paper describes a new committed oblivious transfer protocol based on a first two round string oblivious transfer and bit commitment with XOR. With a first two round string oblivious transfer, the protocol can avoid performing a large number of bit oblivious transfers. And with bit commitment with XOR, zero knowledge proofs are very easy. The protocol is conceptually simple and more efficient. The security and complexity of the protocol are also discussed in this paper.
An ECMQV-based asymmetric authentication scheme is proposed,which enables client authentication with memorable passwords and server authentication with conventional certificates;the client password authentication possesses zero-knowledge-proof security property,which allows using weak passwords;implicit authentication is used to validate server-side entity,which greatly cuts down client computation overhead.AEAS can be integrated into current WTLS framework,resulting in a WTLS extension with higher security and lower computation overhead,which mets wireless terminals' high-security requirements under enterprise remote access scenario.
Fairness is the vitally necessary for application of electronic transaction.A fair protocol is presented for message transfer in electronic commerce.The protocol is designed to assure when the protocol ends,both parties get the expected messages or nothing.The protocol,based on optimistic approach,uses convertible signature scheme and non-interactive zero-knowledge proof to achieve efficient transparent TTP.Also,the protocol generates standard GDH(gap diffie-hellman) signatures as the final non-repudiation evidences.All these efforts make the protocol efficient and easy to be fitted in existing systems.
As China and other countries seek to decentralize the financial practices of their sub‐national governments, designing relevant institutions and rules looms as a major policy issue. The purpose of this paper is to clarify the capital market behaviour of Canadian provincial and municipal governments (PMGs), given their financing choices, and to draw relevant comparisons to American state and local government (SLG) debt financing practices. After identifying relevant elements of the federalism structure in the two countries, the paper compares the institutional rules and roles that comprise the capital acquisition behaviour of sub‐national borrowers. The paper concludes by highlighting key points of difference in this important area of fiscal federalism. Both Canada and the United States can present their market‐oriented approaches to subnational financing as a positive foreign policy force.
To prevent e-cash from double-spending and unlimited increase in the records of databases,an improved offline e-cash system based on elliptic curve cryptography was proposed.The improved system utilizes good properties of elliptic curve cryptography system and adopts zero knowledge proof.Partial blind signature based on elliptic curve cryptography ensures that the e-cash is valid only in the period issued by the bank according to the withdrawal protocol,and the historical record of the e-cash that exceeds the valid period will be removed,which greatly reduce the amount of traffic and effort of calculation and improve the efficiency.The security of the system was improved by adopting the elliptic curve zero knowledge proof in the payment protocol.
New group signature schemes that are secure,effective and shared among different groups are an important direction in re-searching.The group signature scheme based on discrete logarithm problem can be used to share public parameter of the system among different organizations.Further,the main idea of the zero-knowledge proof is used to guarantee the security and efficiency of the scheme.Such sharing represents a high support for a uniform and secure system construction,and is favor to the management and application of the group signature system.
Group-oriented identity authentication is designed to satisfy some special security demands.It help to prevent the cheat of inner fellows and improve the security level and availability of identity authentication system,as well as strengthening the system sur-vivability.Combined with general ElGamal digital signature,shamir secret sharing and zero-knowledge proof,a group-oriented identity authentication scheme is designed,which can effectively resist familiar personate and conspiracy attack.
A non-interactive publicly verifiable protocol based on the intractable problems of discrete logarithm in elliptic curves cryptography is proposed.A non-interactive publicly verifiable zero knowledge proof protocol is designed.A new non-interactive publicly verifiable electronic voting scheme is established.This scheme enables anybody to verify if the shares are correctly distributed.This scheme can protect against the cheating action and is applicable to elections of smaller scale.
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
Historically, infrastructure funds have been strongly debated for infrastructure policies in developing countries. With fiscal austerity and tighter budgets, off government budget cost recovery mechanisms raise interest for the infrastructure policies of rich countries as well. The paper will explore the economic and political rational for infrastructure funds. It will argue that infrastructure funds may be considered to be a mechanism to avoid failures to coordinate between different interests in transport infrastructure policies, leading to distorted infrastructure policies and a waste of resources by political players. Infrastructure policy without politics. In a first part the paper will set the classical public finance arguments on optimal capacity choice and finance of indivisible but congestible goods like infrastructure facilities. It will be shown that in this idealized world, where governments perfectly aggregate the preferences of the infrastructure users and taxpayers, a centralized budget process and a decentralized quasi-market for infrastructure services (like an infrastructure fund) lead to identical outcomes. It will be shown that this outcome depends on assumptions on the feasibility of counterfactual tax and transfer policies. In practice, substantial differences are observed between planned expenditure levels for transport infrastructure, for new investment and particular for maintenance. A dominant explanation of this gap is the weakness of transport policy relative to other portfolios in the policy decision making process. Lobbying and infrastructure policies. Isolating the influence of special interest groups in the political process, the paper will show that, if governments seek campaign contributions and a high share of votes of the population, the lobbying activities lead to a political outcome that is identical to the infrastructure policy in the absence of lobbying activities. That is, the lobbying parties are caught in a prisoners' dilemma from which they would want to withdraw could they do so unilaterally. Wasteful but inconsequential lobbying continues, however, as the lobbying parties fail to coordinate to withdraw from influencing the outcomes of the budget process. The existence of infrastructure funds would enable the society to save the resources wasted in rent seeking activities. Lobbying and the entry of citizen-candidates. In the context of a mobile party structure, where citizen-candidates with own policy profiles might enter party politics, lobbying might lead to a reaction of candidatures for political offices that lead even to a worse outcome for the lobbying contenders than in the case of an agreed abstention from lobbying. In this case, a coordination not to lobby between special interest groups would lead to the avoidance of resources spent in rent seeking activities, a distortion of infrastructure investment and maintenance levels from inducing countervailing party positions and a loss of income of the lobbying parties. Benefits transport infrastructure funds. The paper will argue that establishing transport infrastructure funds can be considered a solution to the distorting influences resulting from lobbying and induced reactions in the party system on infrastructure policy. An initiative to establish infrastructure funds could enable lobbying parties to escape the prisoners' dilemma of being unable to coordinate. For the covering abstract see ITRD E135582.
Facing the assault of domestic and international banking finance transactions,China's urban commercial banks must make finance choice of their own.According to the status quo of China's city commercial banks,their finance market positioning should be serving for finance service for the small-and medium-sized firms;the finance products at the early stage of development should primarily be agent for other's products or co-products developed with others,realizing a decentralized marketing;the main purpose is to strengthen the customer relation,sticking to a principle of tiny profit,not until the customer clusters be stabilized and grandness can take finance as a profitable means;at present,the key is to foster talented persons of finance.
The fundamental questions addressed in this paper are the following: what is the most appropriate approach to organizing the vertical structure of tax administration, and what are the determinant factors that may make an approach more or less optimal in any particular country. We consider the theoretical arguments for and against centralized and decentralized models of tax administration and review the actual practices in a number of countries. The main conclusion is that one size does not fit all; the choices countries make in terms of their level of fiscal decentralization respond to complex agendas, which often involve political objectives. However, given the general approach to fiscal decentralization and, more in particular, revenue assignments, it is possible to identify better and worse approaches to organizing tax administration.
JULES H. Van BINSBERGEN, MICHAEL W. BRANDT, RALPH S. J. KOIJEN
We study an institutional investment problem in which a centralized decision maker, the Chief Investment Officer (CIO), for example, employs multiple asset managers to implement and execute investment strategies in separate asset classes. The CIO allocates capital to the managers who, in turn, allocate these funds to the assets in their asset class. This two-step investment process causes several misalignments of objectives between the CIO and his managers and can lead to large utility costs on the part of the CIO. We focus on (i) loss of diversification, (ii) unobservable appetites for risk of the managers, and (iii) different investment horizons. We derive an optimal unconditional linear performance benchmark and show that this benchmark can be used to better align incentives within the firm. We find that the CIO's uncertainty about the managers' risk appetites increases both the costs of decentralized investment management and the value of an optimally designed benchmark.