Research And Application Of Digital Signature

With the rapid development of information technology and the popularity of the Internet, more and more network applications permeate people’s daily life and promote the development of social productivity at the same time. Information has become valuable resources of various industries and its acquisition and transmission has become a key research focus in international network community. The cryptographic theory, as the cornerstone of information security, can effectively solve the problem of secure communication and privacy preserving, and plays an important role in the field of information security. Digital signature, an important branch of cryptography, is also an important research field in information security because of its unique features and important application.Numerous information needs to be saved and transferred through network. In this process, the participants may deny, forge, pretend or tamper the information in order to get more interests. Although data encryption technology can basically protect data and resist the third party attack, it cannot protect against mutual fraud. Digital signature can solve these problems effectively. Using digital signature, the sender uses his private key to ’sign’ a file and sends the ciphertext to the receiver, and then the receiver can use the sender’s public key to decrypt it. If a signature can be verified with one’s public key, it proves that the signature is signed by and is coming from him, and thus guarantee the secure communication. Digital signature plays an important role in such aspects as certificate authentication, identification and non-repudiation. It has important theoretical significance and practical value in information security. Among various signature schemes, proxy signature can effectively guarantee the secure communication between three parties, and ring signature also attracts the attention of scholars with its efficiency and simple features. These two types of signature are two focuses at present. Rivest, Shamir and Adleman proposed the first digital signature scheme based on the public key cryptosystem, which is the foundation of most of subsequent digital signature research. This paper mainly bases on Mambo’s proxy signature method, Rivest, Shamir and Tauman’s ring signature scheme and bilinear pairings and several mathematical difficulty problems, deeply studies identy-based proxy signature, ring signature and their applications. The main work is as follows:1. We analyze and point out some safety defects existing in the proxy signature scheme proposed by Wu et al., and then proposes a new proxy signature, prove the correctness, public verifiability and un-forgeability of our scheme, and compare its security and efficiency with other two proxy signature schemes.2. Miao et al. proposed an anonymous electronic prosecution scheme. Wang et al broke it and proposed a new one.We propose a new complete anonymous electronic prosecution scheme that is identity-based and can guarantee the anonymity of a prosecutor, which can solve the existing problems of low security and low efficiency. This is a mature anonymous electronic reporting scheme.3. Analyzing the characteristics of the linkable ring signature proposed by Liu, this paper first propose to determine whether two different signatures are signed by the same participant to prevent users from spending repeatedly in the consuming process; and then designs a new electronic consumption scheme based on bilinear pairings. This scheme not only can satisfy the basic requirement of information security but also can prevent repeated electronic consumption.