Security protocols in body sensor networks using visible light communications

The fifth generation (5G) wireless system aims to support body sensor networks (BSNs) by increasing the interconnectivity of electronic devices. BSNs in the 5G era will enable many interesting applications, for example, medical services. In these applications, sensor networks collect sensitive information of individual human beings. Thus, security becomes significantly important in BSNs. However, many key distribution protocols are based on pre-deployed secrets. There are some problems: It is difficult to update pre-deployed secrets after they are compromised, or users want to re-deploy a device node. In this paper, we propose several security protocols including two key establishment protocols for BSNs by using visible light communications (VLCs). These protocols have a number of advantages. First, they can be widely applied in current BSNs without extra conditions because VLCs can be supported in most BSNs. Second, these protocols do not need pre-shared secrets; thus, it is not necessary for users to change pre-shared secrets if they are compromised. Experiments and analysis further show that (1) VLCs based on on–off keying are preferred; (2) computation and communication burden of these protocols are acceptable; and (3) these protocols bring little burden on users.