Résumé : We demonstrate anticipating synchronization between two chaotic laser diodes respectively subjected to incoherent optical feedback and incoherent optical injection. We investigate the robustness of the synchronization with respect to small parameter mismatches and spontaneous emission noise. We show that the gain saturation strongly enhances the synchronization quality. We demonstrate that anticipating synchronization can be applied to cryptographic purposes. We check how difficult it is to intercept a message encoded by chaos shift keying without an adequate replica of the transmitter laser. © 2002 Elsevier Science B.V. All rights reserved.