An identity-based authentication protocol for sensor networks

We proposed an identity-based symmetric key authentication protocol using the Multiple-Key Blom´s key agreement scheme as the underlying cryptographic system. This scheme enables a pair of nodes to compute a secret pairwise key using each other´s identity. The protocol has two modes of operations. In mode 1, the long term pairwise key is used for encryption while in mode 2, the nodes use a randomly generated session key. Communications start in mode 1 and the receiving node is able to authenticate the sender after receiving a single initial message. The protocol subsequently switches to mode 2 if a response is received, if not, communications fall back to using mode 1. The exposure to attacks is minimal and all messages are encrypted using the pairwise keys.