With Forward Security Proxy Blind Signature Analysis And Design

The security of traditional digital signature systems is based on the signing key which is not leaked. Once the signing key is leaked, the security of the system becomes very fragile. To solve this problem, scholars propose many different ways to try to lower the chance of the leakage of the system key in transmission process. However, the general method is not universal and practical.In this thesis, we begin to research the forward-secure proxy blind signature system and the strong forward-secure proxy blind signature system. The main results are as follows:1. The forward-secure proxy blind signature system.(1) We propose the definition of forward security digital signature scheme firstly, including the narrow forward security and the generalized forward security.(2) We introduce the existing proxy blind signatures. Then, we find that the two schemes have not the generalized forward security property.At the same time, we attack the above two existing schemes in the thesis.(3) We propose a new generalized forward-secure proxy blind signature scheme. The new scheme has many security properties, such as generalized forward security, distinguishability, unforgeability, unlinkability, strong blind and so on.2. The strong forward-secure proxy blind signature system.(1) We propose a strong forward-secure proxy blind signature scheme model, and we point out that the cryptographic algorithms in this model can be changed with the different security requirements.(2)We propose two strong forward-secure proxy blind signature schemes. They are based on the one-way hash chain and the thoughts of the random number, and the two systems also have strong forward security property.