  Molecular communication in nanonetworks is an emerging communication paradigm
that uses molecules as information carriers. Achieving a secure information
exchange is one of the practical challenges that need to be considered to
address the potential of molecular communications in nanonetworks. In this
article, we have introduced secure channel into molecular communications to
prevent eavesdropping. First, we propose a Diffie Hellman algorithm-based
method by which communicating nanomachines can exchange a secret key through
molecular signaling. Then, we use this secret key to perform ciphering. Also,
we present both the algorithm for secret key exchange and the secured molecular
communication system. The proposed secured system is found effective in terms
of energy consumption.
