Security for FTTx Optical Access Networks

Passive optical networks (PONs) is the answer to increasing demand on bandwidth and an enabler for Fiber To The x (FTTx) implementation, where x can be Home (FTTH), Curb (FTTC), or Building (FTTB). However, PONs use shared fiber link with broadcast and select type of downstream traffic on single wavelength, which makes it vulnerable to eavesdropping. Security at network level in addition to cryptography is vital to success of FTTx in order to make collection of sample traffic difficult. In this paper, a novel technique that consists of slow wavelength hopping and wavelength sequences cycling techniques are suggested where each Ethernet frame/packet is encoded by single wavelength. Each optical network unit (ONU) will have its own wavelength sequence generated by mapping code matrices to a single network wavelength grid matrix. Multiple wavelengths sequences assignment to a single ONU are cycled in different orders so as to enhance security in order to reduce probability of tracking hopping pattern. This technique can also be combined with a block cipher encryption technique, such as AES, in order to increase the security of the encryption algorithm