Keyword ranking with similarity identification is an approach to find the significant Keywords in a corpus using a Variant Term Frequency Inverse Document Frequency (VTF-IDF) algorithm. Some of these may have same similarity and they get reduced to a single term when WordNet is used. The proposed approach that does not require  any test or training set, assigns sentence  based Weightage to the keywords(terms) and it  is found to be  effective. Its suitability is analyzed with several data sets using precision and recall as metrics.

Cryptographic image block encryption schemes play a significant role in information enabled services. This paper proposes an image block encryption scheme based on a novel three stage selection (TSS) method in a public cloud with reversible cellular automata. Due to the openness of public cloud, different attacks are possible over user sensitive information. The TSS method has three stages and they generate a robust master key with user plaintext as input and produces an encrypted block as key to be sent to authenticated users. An analysis of experimental results shows that this new method has a large key space and immune to brute force attacks, statistical cryptanalysis attacks and chosen plaintext attacks. Also, the encrypted image entropy value could be increased to 7.9988 making it ideal for a best image block encryption for key generation.