Symmetric-key Based Security for Multicast Communication in Wireless Sensor Networks

This paper presents a new key management protocol for group based communications for non hierarchical wireless sensor networks (WSNs), applied on a recently proposed IP based multicast protocol. Confidentiality, integrity, and authentication are established, using solely symmetric key based operations. The protocol features a cloud based network multicast manager (NMM), which can create, control and authenticate groups in the WSN, but is not able to derive the actual constructed group key. Three main phases are distinguished in the protocol. First, in the registration phase, the motes register to the group by sending a request to the NMM. Second, the members of the group calculate the shared group key in the key construction phase. For this phase, two different methods are tested. In the unicast approach, the key material is sent to each member individually using unicast messages, and in the multicast approach, a combination of Lagrange interpolation and a multicast packet are used. Finally, in the multicast communication phase, these keys are used to send confidential and authenticated messages. In order to investigate the validity of the proposed mechanisms, the protocol was implemented in ContikiOS and simulated using COOJA, considering different group sizes and multi hop communication.