Thèse soutenue

Protocoles de communications sécurisées par des séquences chaotiques : applications aux standards de communications , IP via DVB-S et l'UMTS
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Accès à la thèse
Auteur / Autrice : Daniel Caragata
Direction : Safwan El AssadEmil Sofron
Type : Thèse de doctorat
Discipline(s) : Electronique
Date : Soutenance en 2011
Etablissement(s) : Nantes en cotutelle avec Université de Pitesti
Partenaire(s) de recherche : autre partenaire : École polytechnique de l'Université de Nantes

Résumé

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In this thesis we have studied new ways of using chaotic functions to ensure information security. Therefore, we have addressed three themes of research: the security of IP communications over satellite DVB, UMTS security and digital watermarking. Firstly we study the security of unicast and multicast IP communications over satellite DVB. We propose a new security solution for this type of communications that encrypts the IP packet and MAC code and that protects the authenticity and integrity of the ULE header and of the IP packet. This solution uses a multi layer key management system, chaotic functions for the encryption of the data and the generation of the secret keys, a customized PDU for the transport of the keys and an alarm message to restore the synchronization between the ISP and the client. We analyze and propose improvements for the security of the UMTS. The network access is at the heart of UMTS security. The enhancements we propose are: user identification using an improved protocol that ensures the protection of: the permanent identity, the secret key K against cryptographic attacks using a temporary key and the encryption of the messages. The modified protocols for security algorithms negotiation and TMSI updating that make the choices of the serving network visible to the users. Finally, we address the information integrity of JPEG images and we propose a new chaos based fragile watermarking algorithm that is efficient and robust. This algorithm is the result of the cryptanalysis that we have developed against the watermarking algorithm proposed by Wang in 2008. In addition we have also simulated the cryptanalysis using first order Markov chains.