Due to the compromise of the security of the underlying system or machine stonng the key, exposure of the private key can be a devastating attack on a cryptosystem. Key insulation is an important technique to protect ...Due to the compromise of the security of the underlying system or machine stonng the key, exposure of the private key can be a devastating attack on a cryptosystem. Key insulation is an important technique to protect private keys. To deal with the private （signing） key exposure problem in identity-based signature systems, we propose an identity-based threshold key-insulated signature （IBTKIS） scheme. It strengthens the security and flexibility of existing identity-based key-insulated signature schemes. Our scheme＇ s security is proven in the random oracle model and rests on the hardness of the computational Diffie-Helhnan problem in groups equipped with a pairing. To the best of our knowledge, it is the first IBTKIS scheme up to now.展开更多
Knowing the level of efficiency of investment applied in ports of Mexico is relevant information for the design of port policies that contribute to its development and thus to greater freight movement. The objective o...Knowing the level of efficiency of investment applied in ports of Mexico is relevant information for the design of port policies that contribute to its development and thus to greater freight movement. The objective of this paper is to analyze the technical efficiency obtained from International Mexican Ports, through the use of the technique of Data Envelopment Analysis （DEA）. It uses data regarding public and private investment in ports applied during the period 2000-2010 and its influence on the number of Twenty-foot Equivalent Unit （TEU）. Because it has been applied the DEA-CCR （the linear programming model） model input oriented, thus not only the efficiency is calculated in ports, but benchmarking is also obtained to determine the efficient ports that serve as reference to those who were found to be inefficient. The results obtained showed that Manzanillo and Progreso were the most efficient ports. On the other hand, the ports that were not efficient for any of the years reviewed were Mazatlan and Lazaro Cardenas. Generally, public investment has been increasing over the period, and public policies are not designed to allow the ports to have an international projection.展开更多
In this paper,a quantum private comparison protocol is proposed based on bell entangled states.In our protocol,two parties can compare the equality of their information with the help of a semi-honest third party.The c...In this paper,a quantum private comparison protocol is proposed based on bell entangled states.In our protocol,two parties can compare the equality of their information with the help of a semi-honest third party.The correctness and security of our protocol are discussed.One party cannot learn the other's private information and the third party also cannot learn any information about the private information.展开更多
In many auctions,buyers know beforehand little about objects to be sold in the future.Whether and how to reveal information about future objects is an important decision problem for sellers.In this paper,two objects a...In many auctions,buyers know beforehand little about objects to be sold in the future.Whether and how to reveal information about future objects is an important decision problem for sellers.In this paper,two objects are sold sequentially and each buyer's valuation for the second object is k times that for the first one,and the true value of k is sellers' private information.The authors identify three factors which affect sellers' revelation strategies: The market's competition intensity which is characterized by the number of buyers,buyers' prior information about the second object,and the difference degree between two objects which is characterized by k.The authors give not only conditions under which revealing information about the second object in advance benefits the seller,but also the optimal releasing amount of information in the market with two sellers and one seller,respectively.展开更多
基金Supported by the National Natural Science Foundation of China （No. 60970111, 61133014, 60903189, 60903020）.
文摘Due to the compromise of the security of the underlying system or machine stonng the key, exposure of the private key can be a devastating attack on a cryptosystem. Key insulation is an important technique to protect private keys. To deal with the private （signing） key exposure problem in identity-based signature systems, we propose an identity-based threshold key-insulated signature （IBTKIS） scheme. It strengthens the security and flexibility of existing identity-based key-insulated signature schemes. Our scheme＇ s security is proven in the random oracle model and rests on the hardness of the computational Diffie-Helhnan problem in groups equipped with a pairing. To the best of our knowledge, it is the first IBTKIS scheme up to now.
文摘Knowing the level of efficiency of investment applied in ports of Mexico is relevant information for the design of port policies that contribute to its development and thus to greater freight movement. The objective of this paper is to analyze the technical efficiency obtained from International Mexican Ports, through the use of the technique of Data Envelopment Analysis （DEA）. It uses data regarding public and private investment in ports applied during the period 2000-2010 and its influence on the number of Twenty-foot Equivalent Unit （TEU）. Because it has been applied the DEA-CCR （the linear programming model） model input oriented, thus not only the efficiency is calculated in ports, but benchmarking is also obtained to determine the efficient ports that serve as reference to those who were found to be inefficient. The results obtained showed that Manzanillo and Progreso were the most efficient ports. On the other hand, the ports that were not efficient for any of the years reviewed were Mazatlan and Lazaro Cardenas. Generally, public investment has been increasing over the period, and public policies are not designed to allow the ports to have an international projection.
基金Supported by the High Technology Research and Development Program of China (863 Program,2011AA01A107)Beijing Municipal Special Fund for Cultural and Creative Industries(2009)the Beijing Municipal Natural Science Foundation (4112052)
文摘In this paper,a quantum private comparison protocol is proposed based on bell entangled states.In our protocol,two parties can compare the equality of their information with the help of a semi-honest third party.The correctness and security of our protocol are discussed.One party cannot learn the other's private information and the third party also cannot learn any information about the private information.
基金supported by the National Natural Science Foundation of China under Grant Nos.61273206 and 71471069
文摘In many auctions,buyers know beforehand little about objects to be sold in the future.Whether and how to reveal information about future objects is an important decision problem for sellers.In this paper,two objects are sold sequentially and each buyer's valuation for the second object is k times that for the first one,and the true value of k is sellers' private information.The authors identify three factors which affect sellers' revelation strategies: The market's competition intensity which is characterized by the number of buyers,buyers' prior information about the second object,and the difference degree between two objects which is characterized by k.The authors give not only conditions under which revealing information about the second object in advance benefits the seller,but also the optimal releasing amount of information in the market with two sellers and one seller,respectively.
