Application Layer: In the second security layer each node uses a point to point encryption scheme with Meshlium -the Gateway of the network-. This way, even the intermediate nodes of the network (the ones which forward the information to the destination) will not be able to see the sensor data transmitted. Messages are sent using AES, (implemented by the software library) ensuring complete confidentiality and privacy while maintaining the minimum resources of the node in term of computing cycles and energy consumption.