Emerging Trends in ICT Security

Optical networks form the backbone of the Internet and are an integral constituent of the physical layer of these networks. Since the physical layer forms the bottom layer in the open systems interconnection (OSI) model [1], the performance and security of the physical layer and especially optical networks have a critical influence on the six layers above it. For example, the channel capacity of the optical network determines the resources available for encryption processes in the upper layer. The security approach in upper layers is limited by both the processing speed of electronic devices and the capacity availability in the optical network. Fundamental improvements can be achieved for the entire network by increasing the optical network’s performance in terms of channel capacity, data rate, and processing speed. Furthermore, the security of the optical network has an impact on the security of the entire communication system. Since it is inherently risky to build a security system on top of a physical infrastructure that is already under threat [2], defending against threats to the optical network also benefits the security of the upper layer. Optical network security can be effectively protected by fiber-based methods, including alloptical signal processing [3 5], optical key distribution [6 8], optical steganography [9 11], and optical chaos-based communication [12 14]. Fiber-based devices do not radiate an electromagnetic signature and are immune to electromagnetic interference, so the adversary can neither eavesdrop from the leaked information to free space nor jam the fiber channel with electromagnetic waves. Another motivation for securing the network based on optical approaches is that fiber-based devices