Design And Analysis Of Blind Signature Schemes

With the progress of the informatization and the rapid development of computer network, despite the high degree of digitization and networking of information, information security issues become increasingly prominen-t. As an important core technology in the field of information security, Digital signature, which has important applications to ensure information integrity and provide network authentication and nonrepudiation, is one of the main study contents of the modern cryptography. With the in-depth study of the digital signature, many digital signatures which have the special property have been proposed for a variety of applications.As a special digital signature, Blind signature has been widely used in electronic cash and electronic voting system, which can effectively protect users’privacy and adapt to confidentiality demand in many business and administrative activities. In this paper, the author mainly has done below the multi-analysis researches from following several aspects to the blind signature schemes:First, cryptanalysis of the blind signature scheme with message re-covery based on DLP which is proposed by Chu et al. shows that the scheme exists follow security flaws:the attacker can forge blind signa-ture of any message, that is to say it doesn’t satisfy unforgeability; the signer can track the message owner colluded with the designated verifier, that is to say the scheme is linkable. An improved designated verifier blind signature scheme with message recovery was purposed to overcome these security problems. The new scheme satisfies verifiability, unforge-ability, non-repudiation, and unlinkability, and it is a secure strong blind signature scheme.Second, through the security analysis of a forward-secure blind sig-nature scheme which is proposed by Zhang et al., it is shows that the scheme exists follow security flaws:there is error in module computation in blind signature generation phase, causing verifiability of the signa-ture scheme being not valid; attacker can generate blind signature of any messages, that is to say it doesn’t satisfy unforgeability. An improved forward-secure blind signature scheme was purposed to overcome these security problems. Security and efficiency analysis result shows that the new scheme satisfies unforgeability, blindness and forward-security, and has high calculating efficiency.Third, utilizing the Shim’s ID-based signature scheme, a new prov-able secure ID-based partially blind signature scheme is proposed. The scheme is proved to be existentially unforgeable against adaptive chosen message and identity attacks in random oracle model, and the security is reduced to computational Diffie-Hellrnan assumption. Comparing with other ID-based partially blind signature schemes in random oracle model, the proposed scheme has better computational efficiency and less traffic.Fouth, through the security analysis of the proxy blind signature scheme based on DLP which is proposed by Liu et al., it is shows that the scheme exists follow security flaws:a dishonest original signer can forge the proxy signing key, that is to say it doesn’t satisfy strongly un-forgeability; the proxy signer can make a linkage between the signature on original message and the signature on corresponding blind message, that is to say the scheme is linkable. An improved scheme was purposed to overcome these security problems. By modifying the equation of the delegate authorization and the process of blind signature, the new scheme can resist the original signer’s forgery attacks, and also has unlinkability.Last, through the security analysis of designated verifier proxy blind signature scheme with message recovery which is proposed by Yu et al. it is shows that the scheme exists follow security flaws:the designated verifier can impersonate proxy signer to forge proxy blind signature of any message, that is to say it doesn’t satisfy strongly unforgeability; the proxy signer can track the message owner colluded with the designated verifier, that is to say the scheme is linkable. In or-der to resist the designated verifier’s forgery attack and linkability attack, an improved scheme was purposed. The new scheme satisfies strong unforgeability, undeniability, unlinkability, privacy, etc., and it is a secure strong proxy blind signa-ture scheme.