Physical layer cryptography in optical networks: A lattice-based approach

This paper discusses the use of lattice cryptography and chaotic maps to encrypt OCDMA-coded optical flows. Unlike existing approaches, which have mainly focused on optical components such as phase masks and delay lines, our cryptosystem encompasses a secure code construction process. In fact, assuming that a pair of bases (a public basis and a private basis) is associated to every user, the OCDMA code-words are projected on a public basis before being sent so that only the user possessing the corresponding private basis can decrypt the keyword. We show that the projection of a codeword on the public basis of the receiver and the addition of a chaotic error enhances the confidentiality performance of the code. This distribution of this error is generated using a chaotic map. In this work, we study the impact of the parameters of this chaotic map on the robustness of the proposed cryptosystem.