This article addresses an innovative concept to enhance the security for IoT applications in the case of Simultaneous Wireless Information and Power Transfer. This is achieved by integrating a complementary security and identification mechanism through Wireless Power Transfer link within the network of autonomous wireless nodes. This mechanism is implemented at the level of the RF rectifier used to receive energy from a dedicated RF source. A prototype of such RF rectifier has been developed, it generates in real time a backscattered waveform (uplink from the wireless node to the RF source) as function of the parameters of the incoming energy waveform (downlink from RF source) and a digital private key code, generated/available at the level of the wireless node. This uplink waveform can be monitored at the level of the RF source for security/identification purposes implementing an autonomous hardware/physical security layer that operates independently from the communication protocols.