Eavesdropping-Aware Routing and Spectrum/Code Allocation in OFDM-Based EONs Using Spread Spectrum Techniques

In this work, eavesdropping-aware routing and spectrum/code allocation techniques are proposed for elastic optical networks (EONs) using orthogonal frequency division multiplexing (OFDM). To introduce physical (optical) layer security and protect these networks against eavesdropping attacks, spread spectrum (SS) with signal overlapping techniques are used to encode each requested confidential connection. In order to make sense of accessed information and compromise a confidential connection, an eavesdropper will now have to lock on the correct frequency, determine the correct code and symbol sequence among co-propagated overlapped signals, and decode the signal. Different novel policies are presented for the assignment of spectrum and the codes for each confidential demand along with different routing strategies, resulting in an extra layer of security for confidential demands. Depending on the spectrum/code allocation and routing policies utilized, different (extra) levels of security are added for confidential connections while also considering the spectrum utilization, the blocking rate, and the algorithmic time complexity required for connection provisioning.