Chaos Based Secure IP Communications over Satellite DVB Daniel Caragata a , Safwan El Assad a , Ion Tutanescu b and Emil Sofron b a Ecole Polytechnique de l’Universite de Nantes, rue Christian Pauc, BP 50609, 44306, Nantes, France. daniel.caragata@univ-nantes.fr, safwan.elassad@univ-nantes.fr b Universitatea din Pitesti, str. Targu din Vale, nr. 1, 110040, Pitesti, Romania. ion.tutanescu@upit.ro, emil.sofron@upit.ro Abstract. The Digital Video Broadcasting – Satellite (DVB-S) standard was originally conceived for TV and radio broadcasting. Later, it became possible to send IP packets using encapsulation methods such as Multi Protocol Encapsulation, MPE, or Unidirectional Lightweight Encapsulation, ULE. This paper proposes a chaos based security system for IP communications over DVB-S with ULE encapsulation. The proposed security system satisfies all the security requirements while respecting the characteristics of satellite links, such as the importance of efficient bandwidth utilization and high latency time. It uses chaotic functions to generate the keys and to encrypt the data. The key management is realized using a multi-layer architecture. A theoretical analysis of the system and a simulation of FTP and HTTP traffic are presented and discussed to show the cost of the security enhancement and to provide the necessary tools for security parameters setup. Keywords: Satellite communications, chaotic functions, security, Internet Protocol, DVB. PACS: 84.40.Ua. INTRODUCTION A large number of applications, both natural and man-made, are investigated using the approach of chaotic non-linear dynamics. The chaotic behavior seems to be a random behavior; nevertheless its origins are not stochastic. It is the result of a perfectly deterministic process. Another key feature of chaos is its high sensitivity to initial conditions. This means that a very slight change of the initial conditions will have a strong and unpredictable effect on the future states of the chaotic system. In recent years, there has been a significant interest in exploiting chaotic dynamics in communications. Topics which have been explored include chaotic encryption, chaotic spreading codes or chaotic modulations. Due to their apparently random behavior and high sensitivity to initial conditions, chaotic functions have attracted great research interest in data security field too. Thus, a wide range of encryption algorithms, message authentication codes, watermarking algorithms and key management techniques have been proposed and have very good cryptographic properties [12, 13, 15, 16, 17].