Search

We study the n-dimensional deconvolution problem associated with an impulse response function and an (additive) noise function that are both characterised by the same phase-only stochastic spectrum. In this case, it is shown that the deconvolution problem becomes well-posed and has a general solution that is both exact and unique, subject to a re-normalisation condition relating to the scale of the solution. While the phase-only spectral model considered is of limited value in general (in particular, problems arising in the fields of digital signal processing and communications engineering, specifically with regard to the retrieval of information from noise), its application to digital cryptography has potential. One of the reasons for this (as discussed in this paper), is that it provides a method of encrypting data where the diffused plaintext can be effectively embedded in a (phase-only) cipher (subject to the floating point precision used for data processing), thereby fully dissipating the statistical signature of the plaintext in the distribution of the cipher. Further, a decrypt can be generated that is computationally efficient subject to the usual cases of sender and receiver having access to identical algorithm(s) and key(s), deconvolution being equivalent to decryption in the context of the (phase-only) encryption model that is considered. For the two-dimensional case, this approach has a potential weakness in terms of a 'correlation attack' using phase retrieval algorithms and a solution to this problem is provided by introducing a (stochastic) amplitude weighting function. Prototype MATLAB functions are provided in the Appendices that accompany this paper to give readers the opportunity to repeat the computational results presented and extend them further. The functions constitute a symmetric algorithm for encrypting and decrypting full colour images in which the key(s) have been exchanged a priori. In this context, the final part of the paper considers the application of phase-only encryption for key exchange using a Threeway Pass Protocol for which a further prototype MATLAB function is provided for validation and further development of the approach by interested readers. [ABSTRACT FROM AUTHOR]

Cloud computing is the concept implemented to remedy the Daily Computing Problems. Cloud computing is basically virtual pool of resources and it provides these resources to users via internet. It offers a range of services for end users; among which there's Storage as a service. In recent years, Storage in Cloud gained popularity among both companies and private users. However, data privacy, security, reliability and interoperability issues still have to be adequately solved. But the most important problem is security and how cloud provider assures it. In this paper, we have proposed a simple, secure, and privacy-preserving architecture for inter- Cloud data sharing. This architecture is based on an encryption/decryption algorithm which aims to protect the data stored in the cloud from the unauthorized access. [ABSTRACT FROM AUTHOR]

This paper is devoted to the study of a method called Stochastic Diffusion for encrypting digital images and embedding the information in another host image or image set. We introduce the theoretical background to the method and the mathematical models upon which it is based. This includes a comprehensive study of the diffusion equation and its properties leading to a convolution model for encrypting data with a stochastic field that is fundamental to the approach considered. Two methods of implementing the approach are then considered. The first method introduces a lossy algorithm for hiding an image in a single host image which is based on the binarization of the encrypted data. The second method considers a similar approach which uses three host images to produce a near perfect reconstruction from the decrypt. In both cases, details of the algorithms developed are provide and examples given. The methods considered have applications for covert cryptography and the authentication and self-authentication of documents and full colour images. [ABSTRACT FROM AUTHOR]