Research On Signature And Signcryption Based On Certificateless Cryptosystem

The scheme of certificateless signature and certificateless signcryption,which were proposed by combining the certificateless cryptosystem with signature and signcryption,are able to provide the authentication function of information and the encryption authentication of information in the process of information transmission.The certificateless signcryption scheme effectively solved the key escrow problem in identity based signcryption scheme while kept its certificate-free property.They can be widely used in the fields of electronic payment key management and smart power grid.At present,there are some design deficiencies in the certificateless signature and signcryption scheme,which cannot meet the security requirements and the computational efficiency is not high.The improvement process of the scheme has become a hot and difficult point in the research.In view of the above problems,improved scheme of certificateless signature and certificateless signcryption are proposed.The improved certificateless signature scheme binds the user's public key to the hash function,and at the same time increases the verification of the signature parameters and the sender's public key,so as to prevent the user from forging a false signature at will and realize the resistance to the public key replacement attack and the forgery attack of ordinary users.The improved certificateless signcryption scheme does not use bilinear pairings,which improves the computational efficiency to a certain extent.The scheme is constructed by combining hash function with user identity binding and combining public key with private key to generate a new key,so as to enhance the security of the scheme.The certificateless signature is unforgeable based on the hard problem of discrete logarithm under the random oracle model.The certificateless signcryption is confidential and unforgeable based on the hard problem of discrete logarithm on the elliptic curve under the random oracle model.Through the comparison and analysis of the comprehensive evaluation indexes of security and computational efficiency with the previous schemes,the scheme proposed in this dissertation not only ensures the correctness,confidentiality and unforgeability,but also improves the efficiency.This dissertation has 9 figures,5 tables and 66 references...