Digital Signature Theory And Its Applications In Digital Rights Management System

With the rapid development of information society and network communication technologies, information has become the most important resource and wealth. However, as the storage and transmission are operated in open communications network, the information is easily be tampered, forgeried and attacked, thus, information security has become a critical issue. Digital signature technology has provided guarantee for information security. Digital signature has a wide range of applications, while the most important one is digital rights management system. This paper studies the digital signature technology and its application in digital rights management system as follows:(1) According to analysising the principles of error-correcting digital signature, an error-correcting digital signature scheme is presented based on knapsack problem of ultra-increasing vector. The scheme can correct errors in the network transmission. Then prove the scheme's security. The comparison of its efficiency with another three error-correcting digital signature schemes is also given; the result show that the scheme we presents has better performances.(2) Using the technology of bilinear mapping to propose a blind proxy re-signatures scheme, this signature refer to the idea of blind signatures, adds the information blinded features with it. The external and internal security of scheme is proven. It is found that the scheme can assist the chosen adaptive message attack from the external attackers and the re-signature proxy.On the basis of the previous scheme, using the principle of standard model, taking into account the unpractical feature of random oracal model, a blind proxy re-signatures scheme based on standard model was proposed. The scheme was presented using the principle of standard model, so it is practically.A proxy re-signature scheme based on the difficulty assumption of quadratic residues is presented, which is Bidirectional. The scheme is safety under the random oracle model. At the same time, the definition of forward-secure proxy re-signature is given, a corresponding scheme is presented which can maintain the former signature's safety even if current cycle's Signature key has been leaked. (3) An access granting protocol of DRM system based on proxy signature scheme is presented to solve the bottle-neck problem of the signing server because of the large number of users. The proof have been presented to demonstrate that the integer security would not reduce compared multi-signing-sever to single-singing-server.Based on the theory of k-TAA scheme presented by Teranisi, a fair k-times anonymous authentication scheme used of the blind signature is presented. The scheme adds trustee that can easily trace the ID of illegal users and keeps the other properties remain at the same time. The appearance of trustee confirms the security of the scheme. We also give the scheme's properties' discussion.There are two problems in traditional DRM system. One is that the users'ID of the system are public, the other is that the use certificate can just be used for one time which can not be repeated used. Based on the two problems above, according to the fair k-times anonymous authentication scheme, a DRM system based on the representation problem was presented used of the restricted blind signature scheme. The new system solves the two problems above. The proven of the system's correctness and security are given, as well as the efficiency analyze.