Proxy Blind Signature And Its Application

Digital signatures, one of the most important components of cryptography, are the theoretical basis of protecting the integrity and authenticity of information. With the development of the Internet, now common digital signature schemes can not be sufficient for the demand . So many digital special signature schemes have been proposed. These include proxy signatures,blind signatures,proxy blind signatures etc.Chaum etc proposed a blind scheme in 1993. The signer can know nothing of the signed information during signing information. So the signed information can be protected. Mambo etc proposed a proxy signature scheme in 1983.A designated signer called proxy signer could sign the information instead of the original signer. So a valid signature can be produced when the original signer is absent. Tan etc proposed a proxy blind signature scheme, this scheme has the characteristic of the proxy signature scheme and the Blind signature scheme. As a new kind of singing technology, proxy blind signature has been applied to the electronic paying system, mobile agent system, electronic voting, electronic auction, electronic commerce and the security of the Internet.Based on the existent proxy signature and blind signature ,The writer has made some progress in proxy blind signature and its application. At the same time ,we solve the problems existed in e-cash.Main contributions of this paper are summarized as follows:1. The security of several famous proxy blind signatures is analyzed. Based on Okamoto-Schnorr blind signature scheme , a new proxy blind signature is proposed, which possess the characteristic of proxy signature and the anonymity and untraceable of blind signature , and our scheme dose not need a secure channel to transmit the proxy secret key.2. Using the bilinear theory defined on elliptic curve , an new ID-based proxy blind signature scheme is presented, which satisfies the security properties of both proxy signature scheme and blind signature schemes. In this scheme, ID-based public key is not the public key stored in certificate. This scheme can omit the process of getting public key from the system in verification phase, therefore decrease interaction time and reduce the store space. 3. Combine proxy multi-signature with blind signature, an new ID-based proxy blind multi-signature scheme is proposed . One proxy signature can generate a proxy blind multi-signature on behalf of many original signers. This scheme satisfies the security properties of both the blind signature scheme and the proxy multi-signature scheme, and can prevent the attacker from forging the proxy blind multi-signature on message.4. The paper introduce the knowledge of e-cash and as an instance, an applying of the new scheme in e-cash is described. The new proxy blind signature is very useful in real life.