Study On Cost-Effective Digital Signature And Its Applications

ABSTRACT:As one of the basic primitive of public key cryptography,digital signature has been widely used in the electronic world to provide integrity,unforgeability as well as non-repudiation.In this thesis,the efficient digital signature with provable security,security analysis of existing digital signature schemes and the applications in the vehicle ad hoc networks and online payment have been thoroughly investigated.Concretely,this thesis concentrates on the certificateless public key cryptography,identity-based public key cryptography,key insulated public key cryptography,digital signature,signcryption,communication protocol for the vehicle ad hoc networks and anonymous online payment protocol with the support of the principle and methodology of system theory.The contributions of this thesis are summarized as follows.First of all,by incorporating the idea of traditional key-insulated signature and identity-based signature schemes,a certificateless key insulated digital signature has been proposed in this thesis to resist the attack mounted by the malicious key generation center(shorten as KGC),whose attack capability has been analyzed thoroughly.The security of this digital signature has been formally reduced to the well-known computational Diffie-Hellman problem without depending on the random oracle model methology.The proposed certificateless key-insulated signature scheme has the following unique characteristics:(?)This scheme enjoys the advantages of both traditional public key cryptography and identity-based public key cryptography.In other words,this scheme not only eliminates the necessity of the public key certificates in the traditional public key cryptography,but also avoids the key escrow problem existing in the identity-based public key cryptography.(?)The lifetime of the user's private key has been split into several independent time periods such that the leakage of the private key in one time period has no negative effect on the security of the private key associated with this user in other time periods.(?)Different from existing certificateless key insulated signature,the proposed scheme can resist the attack launched by the malicious key generation center.There is room for improvement in the aspect of efficiency in spite of the security enhancement.Second,a certificateless aggregate signcryption scheme has been put forthin this thesis based on the elliptic curve cryptographyby incorporating the idea of certificateless cryptography,signcryption and aggregate signature schemes.Then,the security of this scheme is formally reduced to the computational Diffie-Hellman problem using the random oracle model.The proposed certificateless aggregate signcryption sheme features with the following characteristics:(?)This scheme possesses the merits of both traditional public key cryptography and identity-based public key cryptography.(?)This scheme can provide confidentiality,integrity,non-repudiation as well as unforgeability in a single logic step.(?)The proposed scheme outforms the exising schemes in terms of computational cost and communication overhead because of the properties of elliptic curve cryptography and aggregation.Based on the signcryption scheme,a road surface monitoring system has been proposed for the vehicle ad hoc networks.Comparind with existing systems,our system can offer stronger security as well as better efficiency.There is room for improvement in the aspect of security proof in spite of the efficiency and security enhancement.Third,by considering the design rationale behind the certificateless signature and proxy re-signature,a certificateless proxy re-signature has been proposed in this thesis without depending on the expensive bilinear pairing function.Then,the security of the proposed scheme has been formally reduced to the computational Diffie-Hellman problem in the random oracle model.The proposed certificateless proxy re-signature scheme features with the following properties.(?)The proposedscheme can avoid the disadvantages of public key certificates as well as key escrow problem at the same time.(?)An untrusted third party can be authorized to translate a signature from party A to another signature from party B on the same message.The private key of party A or party B will not be disclosed to this party during the translation.Meanwhild,the delegated party is not allowed to generate signature in the name of party A or B.(?)The expensive bilinear pairing functionis eliminated in the construction of this digital signature scheme and thus the proposed scheme outperforms the existing work.Based on the proposed certificateless proxy re signature scheme,an anonymous payment protocol has been put forth in this thesis.This protocol can not only ensure the integrity,non-repudiation and unforgeability of the payment information from payer,but also guarantees the privacy of the payer's identity.There is room for improvement in the aspect of security proof in spite of the efficiency and security enhancement.