Wireless body area network (WBAN) has been identified as one of the promising wi-fi sensor technology for improving healthcare service, thanks to its capability of seamlessly and constantly exchanging medical statistics in real time. However, the shortage of a clear in-depth defence line in one of these new networking paradigm could make its potential users worry about the leakage in their private data, specifically to those unauthenticated or even malicious adversaries. On this project, we present a pair of efficient and light-weight authentication protocols to permit remote WBAN users to anonymously enjoy healthcare service. Especially, our authentication protocols are rooted with a unique certificateless signature (CLS) scheme, which is computational, efficient, and provably secure towards existential forgery on adaptively selected message attack in the random oracle model. Also, our designs ensure that application or service providers have no privilege to disclose the actual identities of users. Even the network manger, which serves as private key generator within the authentication protocols, is prevented from impersonating valid customers. The overall performance of our designs is evaluated thru both theoretic analysis and experimental simulations, and the comparative research demonstrate that they outperform the existing schemes in terms of better trade-off among desirable security properties and computational overhead, nicely meeting the needs of WBANs.