With Research And Improvement, To Secure Digital Signature

With the development of computer and network technologies, human beings have entered into the information era, thus the security problem of information has become the fundamental matter. The digital signature is one of the core techniques in information security. It has been widely used in military,politics,diplomacy, etc, and has been playing an irreplaceable role in the fields of identity authentication,data integrity and non-repudiation, etc. Digital signature will become more and more popular after the e-signature law is carried out. Facing various application backgrounds, it has more practical significance to study digital signatures having different features. We focus on analyzing forward-secure digital signatures in this paper. The main work is as follows:1. The history and development of digital signature is summarized, and its principle and classification are described. At the same time, proxy signature and forward-security of digital signature are easily introduced.2. A designated-verifier forward-security signature scheme is proposed. By analyzing the H-W scheme, we indicate that it is attacked easily by the attacker, so it is not secure. Based on the original scheme, we propose a designated-verifier signature scheme. The new scheme overcomes the shortage of the original scheme, and its security is discussed.3. A new forward-security anonymous proxy signature is proposed. By analyzing the W-Z scheme, we indicate that it is attacked easily by the original signer and verifier, and the identity of proxy signer can't be found definitely during the traceable process. To overcome the shortage, we give an improved scheme. It can not only resist the attack but also reveal the identity of proxy signer. So, it has the property of traceabihty.4. A new designated-verifier proxy signature is presented. It is not only forward-secure but also anonymous and traceable.