Certificateless signature combines the advantages of identity-based cryptosystem and traditional public-key cryptosystem to solve the problems of complex public key certificate management and key escrow. Wu and Jing proposed a strongly unforgeable certificateless signature scheme whose security does not depend on the ideal random oracle. In this paper

two types of forgery attacks are proposed for the security of this scheme. The analysis results show that this scheme cannot achieve strong unforgeability and is insecure under the "malicious-but-passive" key generation center attack. To enhance the security of this scheme

an improved certificateless signature scheme is presented. The improved scheme is proved to be strongly unforgeable against adaptive chosen-message attacks and can also resist malicious key generation center attacks. In addition

the improved scheme has lower computational overhead and shorter private key length

and can be applied to blockchain

Internet of vehicles

wireless body area network and other fields.