NEW IMAGE ENCRYPTION METHOD BASED ON ICA

ABSTRACT In the last decade, Independent component analysis (ICA) becomes one of the most important signal processing tools. Many algorithms have been proposed to separate successfully monodimensional signals from their observed mixed signals. Recently, ICA has been applied to face recognition problem. In this manuscript, a new idea for image encryption and decryption schemes, based on ICA, is proposed. Using some mixing procedure as an encryption method, one can hide useful information transmitted over wireless channels. The main idea of our approach is to secure the transmitted information at two levels: classical level using standard keys and second level (spatial diversity) using independent transmitters. In the second level, a hacker should intercept not one channel but all of them in order to retrieve the information. At designed receiver, one can easily apply ICA algorithms to decrypt the received signals and retrieve the information

Nouvelle méthode optique de compression et de cryptage simultanés des images (fixes/vidéo) pour les systèmes télécommunication

The main objective of my PhD thesis is to propose and validate the principle of a new optimized simultaneously optical compression and encryptions method of multiple images (pictures or coming from a video sequence). Indeed, most compression and encryption methods are optimized in a separate manner and used in cascade. However, both are related and influence each other. This leads to decrease the quality of reconstructed images and to increase their implementation complexity. To overcome these problems, we propose to perform these two operations (i.e. compression and encryption) together in a dependent manner. In addition, we propose different optimizations of compression and plan to increase the encryption level of our system while keeping a good compression ratio. For that, we used a specific segmentation technique specially adapted to the Fourier domain in order to merge together several target images and to create several encryption keys. Those keys (amplitude and/or phase) are used in the image plane and in the Fourier plane. To decrypt the transmitted information, it is necessary to have both encryptions keys and the used spectral segmentation technique.L’objectif de cette thèse est de proposer et valider une nouvelle méthode optique optimisée de compression et de cryptage simultanés des images (fixes ou issues d’une séquence vidéo). En effet, la plupart des méthodes de compression et de cryptage des images sont proposées d’une manière séparée et sont implantées en cascade (l’une après l’autre). Cependant les deux méthodes sont liées et l’une influence l’autre. Cela conduit à une baisse dans leurs performances et une complexité dans leur réalisation. Pour palier à ces problèmes, nous proposons de réaliser ces deux opérations (à savoir la compression et le cryptage) simultanément et d’une manière dépendante. Pour ce faire, notre approche de compression propose une opération de filtrage spectrale basée sur un critère de sélection et une fusion spéciale visant à multiplexer les informations représentatives de chaque image cible. De plus, nous cherchons à augmenter le niveau cryptage de notre système tout en gardant un bon taux de compression. Pour ce faire, nous utilisions une technique de segmentation spécialement adaptée au domaine de Fourier. Cette technique est basée sur l’utilisation, dans le plan image et dans le plan de Fourier, d’un ou plusieurs masques (clés d’amplitude et/ou de phase). Pour décrypter, il sera nécessaire de disposer à la fois des images qui ont servi à fabriquer ces masques de cryptage ainsi que de la technique de segmentation spectrale

New image encryption method based on ICA

International audienceIn the last decade, Independent component analysis (ICA) becomes one of the most important signal processing tools. Many algorithms have been proposed to separate successfully monodimensional signals from their observed mixed signals. Recently, ICA has been applied to face recognition problem. In this manuscript, a new idea for image encryption and decryption schemes, based on ICA, is proposed. Using some mixing procedure as an encryption method, one can hide useful information transmitted over wireless channels. The main idea of our approach is to secure the transmitted information at two levels: classical level using standard keys and second level (spatial diversity) using independent transmitters. In the second level, a hacker should intercept not one channel but all of them in order to retrieve the information. At designed receiver, one can easily apply ICA algorithms to decrypt the received signals and retrieve the information. Keywords: Decorrelation, Second order Statistics, Whiteness, Blind separation of sources, Image Encryption / Decryption