Phase-Only Digital Encryption

Abstract—We study then-dimensional deconvolution prob-lem associated with an impulse response function and an(additive) noise function that are both characterised by thesame phase-only stochastic spectrum. In this case, it is shownthat the deconvolution problem becomes well-posed and has ageneral solution that is both exact and unique, subject to are-normalisation condition relating to the scale of the solution.While the phase-only spectral model considered is of limitedvalue in general (in particular, problems arising in the fieldsof digital signal processing and communications engineering,specifically with regard to the retrieval of information fromnoise), 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 thediffused plaintext can be effectively embedded in a (phase-only)cipher (subject to the floating point precision used for dataprocessing), thereby fully dissipating the statistical signatureof the plaintext in the distribution of the cipher. Further,a decrypt can be generated that is computationally efficientsubject to the usual cases of sender and receiver havingaccess to identical algorithm(s) and key(s), deconvolution beingequivalent to decryption in the context of the (phase-only)encryption model that is considered. For the two-dimensionalcase, this approach has a potential weakness in terms of a‘correlation attack’ using phase retrieval algorithms and asolution to this problem is provided by introducing a (stochastic)amplitude weighting function. Prototype MATLAB functionsare provided in the Appendices that accompany this paper togive readers the opportunity to repeat the computational resultspresented and extend them further. The functions constitute asymmetric algorithm for encrypting and decrypting full colourimages in which the key(s) have been exchangeda priori. In thiscontext, the final part of the paper considers the applicationof phase-only encryption for key exchange using a Three-way Pass Protocol for which a further prototype MATLABfunction is provided for validation and further development ofthe approach by interested readers

The Impact of electricity blackouts on women time-use: a case study of Emakhandeni suburb in Bulawayo.

The project sought to investigate the impact of electricity blackouts on women time use using Emakhandeni suburb as a case study. The study was carried out because they was an outcry by the residents of the suburb that the frequency of blackouts had turned into a crisis. The study focused on understanding the impact of blackouts on women in their households given that they bear the burden of carrying out the reproductive roles in their families. Caroline Moser and other scholars argue that women are constrained on time due to the triple roles they perform in societies. A qualitative approach was used in this study. Data was collected from a convenient sample of predominantly female respondents through use of focus discussion, face to face individual’s interviews and observations. This study has shown that blackouts negatively affect women’s ability to plan for the day, disrupt their activities and worsens their time constraints. Provisions of electricity should be viewed with gender lens as blackouts have tendered to affect women more than men at household leve

An Analysis of the Differences in Vulnerability to Climate Change: A Review of Rural and Urban Areas in South Africa

Evidence is unequivocal that rural and urban areas in South Africa are vulnerable to the impacts of climate change; however, impacts are felt disproportionately. This difference in vulnerability between rural and urban areas is presently unclear to guide context-based climate policies and frameworks to enhance adaptation processes. A clear understanding of the differences in vulnerability to climate change between rural and urban areas is pertinent. This systematic review aimed to explore how vulnerability to climate change varies between rural and urban areas and what explains these variations. The approach was guided by the Intergovernmental Panel on Climate Change vulnerability framework incorporating exposure, sensitivity, and adaptive capacity dimensions integrated into the Sustainable Livelihood Framework. The review used 30 articles based on the search criteria developed. The findings show differences in vulnerability to climate change between rural and urban areas owing to several factors that distinguish rural from urban areas, such as differences in climate change drivers, infrastructure orientation, typical livelihood, and income-generating activities. We conclude that vulnerability varies with location and requires place-based analyses. Instead of blanket policy recommendations, localized interventions that enhance adaptation in specific rural and urban areas should be promoted

Cost Drivers Study of the Zimbabwean Economy

This study was carried out in response to a request by the Ministry of Industry and Commerce, to ZEPARU to conduct an evaluation of cost drivers affecting the competitiveness of Zimbabwe’s businesses. Factors identified in ZEPARU’s previous studies which were considered in this study included labor, power, water, finance, transportation costs, tariffs and trade taxes, taxation and information technology. The study extended the analysis to consider the following factors: lack of scale- under performance of agriculture; failure by government to pay for goods and services on time; and lack of change. These factors were raised by company executives and business associations during interviews as negatively impacting on costs and competitiveness