The growth of the Internet has opened up tremendous opportunities for cooperative computations where the results depend on the private data inputs of distributed participating parties. In most cases, such computations are performed by multiple mutually untrusting parties. This has led the research community into studying methods for performing computation across the Internet securely and efficiently. This thesis investigates security methods in the search for an optimum solution to privacy- preserving distributed statistical computation problems. For this purpose, the nonparametric sign test algorithm is chosen as a case for study to demonstrate our research methodology. Two privacy-preserving protocol suites using data perturbation techniques and cryptographic primitives are designed. The first protocol suite, i.e. the P22NSTP, is based on five novel data perturbation building blocks, i.e. the random probability density function generation protocol (RpdfGP), the data obscuring protocol (DOP), the secure two-party comparison protocol (STCP), the data extraction protocol (DEP) and the permutation reverse protocol (PRP). This protocol suite enables two parties to efficiently and securely perform the sign test computation without the use of a third party. The second protocol suite, i.e. the P22NSTC, uses an additively homomorphic encryption scheme and two novel building blocks, i.e. the data separation protocol (DSP) and data randomization protocol (DRP). With some assistance from an on-line STTP, this protocol suite provides an alternative solution for two parties to achieve a secure privacy-preserving nonparametric sign test computation. These two protocol suites have been implemented using MATLAB software. Their implementations are evaluated and compared against the sign test computation algorithm on an ideal trusted third party model (TTP-NST) in terms of security, computation and communication overheads and protocol execution times. By managing the level of noise data item addition, the P22NSTP can achieve specific levels of privacy protection to fit particular computation scenarios. Alternatively, the P22NSTC provides a more secure solution than the P22NSTP by employing an on-line STTP. The level of privacy protection relies on the use of an additively homomorphic encryption scheme, DSP and DRP. A four-phase privacy-preserving transformation methodology has also been demonstrated; it includes data privacy definition, statistical algorithm decomposition, solution design and solution implementation.

After two world wars, the West European Economy goes through serious recession. Through the cold war, the representatives of west European countries, German and France, feel that they must cooperate. Hence, by the bases of economic co-operations, the West Europe starts to integrate their resources and political alliances. From the ¡§Economic Community (EC)¡¨ to ¡§Economic and Monetary Union (EMU)¡¨, most West European countries go through several obstacles, like the Collapse of Bretton Woods System in 1971 and the European Crisis in 1992,¡K¡K, etc. Finally, in 1th, Jan., 1999, 11 countries of European Union establish EMU and expect to take Euro as their single currency formally in 2002. They also establish European Central Bank (ECB) to execute the Euro zone¡¦s single monetary policy. The status of Euro after 1th Jan., 1999 is the purpose of this study. This article tries to use the Exchange Rate decision theories, Purchasing Power Parity (PPP) and Interest Rate parity (IRP), to investigate the relationship between Euro and USD. From several statistical empirical tests, it reveals that the trends of Euro couldn¡¦t correspond with the theoretical wants, ie PPP and IRP can¡¦t catch the trends of Euro. By the outcome of ¡§Sign Test¡¨ and ¡§Wilcoxon Sign-Rank Test¡¨, it can be found obviously that the Euro indeed is undervalued from the establishment to Apr., 2000 if we don¡¦t take the transaction costs into account. As a result of the outcome of empirical finds, the article starts to investigate the reasons why the theoretical values from exchange rate decision theories are not equal with real ones. One is that if the empirical models ignore some important factors which lead to the biases of models¡Fthe other is if Euro is undervalued during this observation periods. From the economic macro-environmental analyses, the article can infer that because of the Kosov Wars, Russian economic reform problems, the increase of short interest rate gap between USD and Euro, the different economic reform paces among member countries of EMU,¡K¡K, etc. result in the main factors of the weak currency - Euro.