The Research Of Forward Secure Proxy Blind Signature Scheme

The application of information technology has changed the traditional transaction processing method of human beings and has promoted the progress, and development of the society. Meanwhile, people have increasingly realized the importance of information security in the national security and social stability. As one of the important ways to ensure the information security, the digital signature technology can realize the identity authentication and guarantee the information integrity to meet the requirements of data network transmission. In order to satisfy the application demands of different occasions, more and more digital signature schemes with special properties have been proposed, one of them is the forward secure proxy blind signature scheme. It has the characteristics of ordinary proxy blind signature scheme, but also with the forward security. It can guarantee the safety of all signatures signed before the key exposures, which has practical significance.The forward secure proxy blind signature schemes are studied in this thesis, the main work is described as follows:First of all, by analyzing a forward secure proxy blind signature scheme, it is pointed out that the scheme does not resist the original signer’s forgery attack, which means that a dishonest original signer is able to forge the proxy signing key, and the scheme does not satisfy the untraceability, which means that a proxy signer can make a linkage between a message signature and the corresponding blind message signature. To solve the above problems, an improved forward secure proxy blind signature scheme is presented. By improving the method of the delegate authorization and the process of blind signature, the improved scheme overcomes the security problems existing in the original scheme. Then based on discrete logarithm problem and quadratic residue problem, the security properties of unforgeability, blindness and forward security of the scheme are analyzed.Secondly, through the security analysis of a forward secure certificateless proxy blind signature scheme, it is found that the scheme does not satisfy the unforgeability and the blindness. To address the above problems, a new forward secure certificateless proxy blind signature scheme is presented. It overcomes the security drawbacks existing in the original scheme by improving the proxy key generation process and the blind signature process. The new scheme also satisfies the backward security by embedding the one-way hash chain in the signature process. Furthermore, there is no need of setting up a confidential channel between key generation center and users, which reduces extra expense. The security analysis shows that the new scheme meets the security requirements of a forward secure certificateless proxy blind signature scheme.Finally, we summarize the research work in this thesis and present the main research direction in the future.