On The Security Of A Novel Construction Of Certificateless Aggregate Signature Scheme For Healthcare Wireless Medical Sensor Networks

Recently, Qiao et al. proposed a novel construction of certificateless aggregate signature (CLAS) scheme to ensure the integrity and authenticity of medical data in healthcare wireless medical sensor networks (HWMSNs). They first created an underlying certificateless signature (CLS) scheme, and then proposed a CLAS scheme from the underlying CLS scheme by adding an aggregation algorithm and a verification algorithm. In this paper, we point out that their CLS scheme is insecure because the Type I adversary can forge valid signatures. That is, the unforgeability is not actually captured by their CLS scheme. Finally, we map our cryptanalysis to the practical application. That is, in the practical application of HWMSNs, the attacker can launch real attack to their CLS scheme using our cryptanalysis to forge signatures. Therefore, Qiao et al.'s CLS scheme can be totally broken.