On the Security of Multi-Receiver Certificateless Generalized Signcryption Scheme for WBANs

In Wireless body area networks (WBANs), the physiological parameters monitored by wearable devices are sensitive data of patients. To ensure the privacy of such data, Shen et al. proposed a multi-receiver certificateless generalized signcryption scheme to support multidisciplinary team treatment. Although they claim that their scheme can resist Type I attacks and provide the unlinkability of ciphertext, our analysis found that their scheme is insecure. Specifically, it is neither resistant to public key replacement in Type I attacks, nor does it satisfy the claimed unlinkability of ciphertext. After giving the corresponding attacks, we analyze the reasons underlying these attacks and provide the corresponding suggestions to overcome them.