Design And Analysis Of Threshold Proxy Signature Scheme

Based on the idea of threshold which authorizes proxy signer's right to a certain group of people, the threshold proxy signature is designed for limiting the proxy signer's rights. In a (t, n) threshold proxy signature scheme, the signing right is distributed to n vicarious signers, and the proxy signer's right will take effect on condition that no less than t vicarious signers issue together. Threshold proxy signature receives extensive concerns because of its high stand of security, decentralization of management, as well as some other advantages. This thesis researches the threshold proxy signature from two aspects: one is to analyze the security of current threshold proxy signature schemes; the other is to design and analyze the new schemes. This thesis is mainly about the following chapters:1. Introducing some classic threshold proxy signature schemes which are significant to the development of science and their security analysis; by analyzing the bug of Hsu05 scheme, we found that the scheme can not resist original signer's spurious attack.2. Designing a (t, n) threshold proxy signature scheme without a trusted party. This scheme can resist t vicious signers' conspiracy attack and original signer's spurious attack.3. By concealing the singers' secret key which generated from the trusted party's secret key under the condition that we had a trusted party, we present a (t, n) threshold proxy signature scheme which is based on the abstruseness of Discrete Logarithm problem; meanwhile, Based on the Elliptic Curve Cryptosystem, this chapter presents a (t, n) threshold proxy signature scheme by choosing a secret polynomial of n degree. In the scheme, all of signers can not calculate the secret polynomial. These two new schemes can resist the conspiracy attack and original signer's spurious attack.4. Proposing an Identity-Based threshold proxy signature scheme from bilinear pairings and proving that the scheme satisfied security properties such as identifiability, nonrepudiation and unforgeability.5. Analyzing the proxy signature scheme with specified verifier by H.-U. Park and I.-Y Lee, and proving that the scheme can neither meet the demand of being designated by original signer nor resist original signer's spurious attack. Offering a better scheme and presenting its security analysis. In addition, based on the better scheme, we proposed a threshold proxy signature scheme with specified verifier and proved that it can meet the demand of being designated by original signer and resist original signer's spurious attack.