With the Internet’s rapid development, network communication becomes one of people’smain ways to communicate. So the network information security problem receives more andmore attention. Digital signature, one of the key techniques to ensure the network informationsecurity, plays an important role in both theoretical research and real life.In everyday life, people often delegate their signing rights to reliable agents by passingstamp. But in information society, common digital signature can’t delegate the signing right in asimilar way. To solve the above-mentioned problem, Mambo et al. put forward proxy signature, adigital signature with authorization mechanism. With the deepening of the theory research andthe constant change of the real demand, some proxy signature schemes with special propertiesreceive more and more people’s favors.This paper mainly aims at the designated verifier (t, n) threshold proxy signature and theforward secure designated verifier proxy signature. And the following is the work concludes.1. This paper firstly takes a brief look at the proxy signature’s research background,significance and the current situation. And then, it gives a brief account of some mathematicalknowledge, concept, properties, classification of proxy signature, reviews the basic ideas offorward security and (t, n) threshold. Finally, it reviews some kinds of classical proxy signatureschemes and gives brief security analyses.2. This paper reviews and analyzes an existing (t, n) threshold proxy signature scheme,points out its flaws and gives an improvement. Then, it integrates designated verifier into theimprovement to design a designated verifier (t, n) threshold proxy signature scheme.Performance analysis shows that the first improvement overcomes the original scheme’s flaws,the second has a certain increase in the efficiency, and both the two improvements satisfy all thesecure properties of proxy signature.3. To reduce the key exposure loss, this paper integrates forward security into proxysignature to come up with a forward secure proxy signature scheme with designated verifier. Andthen, it integrates forward security into threshold proxy signature to propose a forward secure (t,n) threshold proxy signature scheme with designated verifier. Performance analysis shows thatboth the two new schemes realize forward security. The first new one has high efficiency, thesecond has no trusted center, which improves its own security, and the signature has properties ofmessage recovery, which reduces the costs of the signature transmission. |