Wireless Sensor Networks suffer from power and energy consumption issues because the batteries used are small and power-limited. Mobile Cloud Computing suffers from several security threats such as integrity and privacy issues. The integration of both areas results in better energy conservation and a more secure environment. Thus, this research introduces a secure energy-efficient platform that reduces the energy consumption and maintains privacy. The security approach of the platform utilizes a modified version of the Sharing-based Scheme and a Precision-enhanced and Encryption-mixed Privacy-preserving Data Aggregation scheme. The first supports both authentication and encryption using XOR gates, while the second is a slicing, secure data aggregation protocol that enhances both security and energy. For energy consumption reduction, asynchronous scheduling duty cycling based on Location, Priority and PreConfiguration is introduced. The results show that the platform depends on the rate of sensing, frequency of sending data, data size, location and number of sleeping sensors, and smartphone battery capacity. In the case of less frequent rates and lower data sizes, the operational energy consumption is 1% of the mobile's entire battery capacity. In the case of sensors sleeping next to the sink, the cost is reduced by over 70% with an additional cost of 20% over the un-secured network. The simulations show that the encryption cost decreases as the number of sensors increases. Furthermore, when the number of sensors increase, the distance between the node decreases and therefore more sensors are tending to sleep, which leads to less energy consumption. As a result, the platform introduced in this work outperforms existing schemes for large numbers of sensors (greater than 300 sensors) with an additional average security cost of 2.96%. (C) 2019 Elsevier B.V. All rights reserved.