Wireless Body Area Network (WBAN) is gaining popularity due to its large scale of applications in eHealth. Due to its critical and real-time nature, eHealth care system must provide security, privacy, and quality of service (QoS) support, in order to provide an efficient, valuable and fully reliable assistance to patients. This paper studies packet scheduling schemes for realtime transmission in WBAN with proper security and privacy. Real-time and non real-time traffic are classified to minimize the waiting time of the eHealth application's data traffic. An efficient secure data transmission scheme in WBAN is proposed with data integrity. The scheme is user-centric and the secure key is shared among all sensors in a WBAN to minimize any additional memory and processing power requirements. Security analysis and numerical results demonstrate that our scheme can minimize the mean waiting time of a real-time traffic in WBAN and provide proper security and privacy.