On The Study Of Some New Digital Signature Scheme

Information society is being pushed into a new advanced stage by high de-velopment speed of communication technology,which have made a great effect on military, commerce, and finance etc. A large number of data and information has been transmitted and saved,such as the personal credit card account, research, per-sonal files.Therefore, the safety of it has been attached more importance, for they may be stolen, exposed, tampered and soon as the time go by. As people become more and more cling to the network. Information safety has become a new subject in the area of information technology. It involves Information, Computer Science and Cryptology and other science knowledge. The core of the Information Safety is cryptology, while digital signature is one of the main study content of the cryp-tology digital signature, namely to sign the information by cryptology. It plays a irreplaceable role in identity-authentication, data integrity, and it has been applied widely in the modern informational society.The main research content of this thesis involves the identity-based digital signature, in the system of Elliptic Curve Cryptography(ECC), which includes the threshold signature scheme based on bilinear pairing and the identity-based proxy verifiably encrypted signature scheme. The main contribution are as following:(1). On the based of the research of digital signature, threshold scheme and the digital signature system based on identity.The verified threshold scheme based on bilinear has been proposed, which not only have the advantage of Elliptic Curve Cryptosystem but also decrease the calculative amount by the application of the bilinear pairing, as well as to be more poverful. Therefore, it is safer and more practical.(2). On the based of the research of proxy signature scheme and verifiably en-crypted signature scheme. The identity-based proxy verifiably encrypted signature scheme has been proposed.In this paper, we extend verifiable encrypted signature to propose a proxy verifiably encrypted signature scheme. It inherits all security requirements of verifiably encrypted signature and proxy signature.then a detail scheme is given and we also show that the scheme is provably secure in the random oracle model. The security of the scheme is related to computational Diffie-Hellamn problem. It is an open problem to construct an efficient proxy verifiably encrypted signature scheme without random oracle.