Within Wireless Body Area Networks (WBANs), wearable devices (WDs) capture vital parameters and process this information. The processed data is then conveyed to a wearable device controller (WDC) before being securely archived within a medical server. Data privacy preservation becomes imperative, preventing unauthorized access and potential compromise. The focal point of the presented research centers on safeguarding data privacy. This objective is accomplished through a two-fold approach: firstly, by encrypting the data within the wearable device controller before storage in the server; secondly, by regulating access to the data for different entities seeking to retrieve it. The innovation of this work lies in its emphasis on ensuring privacy within the wearable device controller itself. It is shown that privacy is obtained using minimum computations. Also, security analysis is performed by identifying various threats and how it is addressed. The encryption process, key generation, and key refreshing are executed employing the MATLAB programming environment.