Research On The Proxy Signature System

In the real world, people often delegate some of their right, such as signing rights, to a reliable proxy. The method to delegate signing rights is seal for its convenient transforability among people. Digital signature is the electronic simulation of handwritten signature but it doesn't provide the function of delegation. In order to solve this problem, the concept and the related properties of proxy signature was firstly proposed by Mambo, Usuda, and Okamoto in 1996. The proxy signature is becoming a hot issue in the digital signature field. Now, many proxy signature systems have been presented with good properties and the proxy signature is applied wildly in the mobile proxy, the electron commerce and electron vote. However, there are some questions needed to further consideration about current proxy signature. Base on previous study, more study is done as follows.1. Most current systems are based on Kim's proxy-protected proxy signature system which is a typical proxy system, but the provable-security of this system has not been proved. Therefore, using the method of the formalization, the security property of Kim's proxy-protected proxy signature system which based on schnorr system with orcal model in face of the adapt pick message attacking is analyzed.2. By the means of the cryptanalysis on some current proxy system, the limitation in security is found in the second class of the proxy multi signature system. Then the system is proved and the property of security is discussed.3. Using the property of the proxy signature and the blind signature, a more efficient new proxy blind signature system is designed and its property is analyzed.