title: Public-channel cryptography based on mutual chaos pass filters.
abstract: We study the mutual coupling of chaotic lasers and observe both experimentally and in numeric simulations that there exists a regime of parameters for which two mutually coupled chaotic lasers establish isochronal synchronization, while a third laser coupled unidirectionally to one of the pair does not synchronize. We then propose a cryptographic scheme, based on the advantage of mutual coupling over unidirectional coupling, where all the parameters of the system are public knowledge. We numerically demonstrate that in such a scheme the two communicating lasers can add a message signal (compressed binary message) to the transmitted coupling signal and recover the message in both directions with high fidelity by using a mutual chaos pass filter procedure. An attacker, however, fails to recover an errorless message even if he amplifies the coupling signal.
authors.affiliation: Department of Physics, Bar-Ilan University, Ramat-Gan, 52900 Israel.
authors.forename: Einat
authors.initials: E
authors.lastname: Klein
authors.forename: Noam
authors.initials: N
authors.lastname: Gross
authors.forename: Evi
authors.initials: E
authors.lastname: Kopelowitz
authors.forename: Michael
authors.initials: M
authors.lastname: Rosenbluh
authors.forename: Lev
authors.initials: L
authors.lastname: Khaykovich
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kinzel
authors.forename: Ido
authors.initials: I
authors.lastname: Kanter