Some Cryptographic Techniques For Secure Data Communication

This thesis investigates conventional and public key cryptographic techniques for secure data communication. Block and stream cipher methods to provide secure communication over an insecure channel are discussed with particular reference to the Data Encryption Standard (DES) algorithm. A microprocessor based data encryption interface unit has been designed and constructed using the DES to provide both communication and file security. Several chaining techniques using the system have also been investigated enabling a study of their error characteristics, speed of operation, level of security and their ability to overcome difficulties due to data redundancy and structure. A statistical analysis of the randomness of the output sequences in each of these techniques has been made. Furthermore, the developed system can be used on the Prestel public network allowing storage and retrieval of completely and partly encrypted frames of information on the Prestel database

Sustainable food security in India—Domestic production and macronutrient availability

<div><p>India has been perceived as a development enigma: Recent rates of economic growth have not been matched by similar rates in health and nutritional improvements. To meet the second Sustainable Development Goal (SDG2) of achieving zero hunger by 2030, India faces a substantial challenge in meeting basic nutritional needs in addition to addressing population, environmental and dietary pressures. Here we have mapped—for the first time—the Indian food system from crop production to household-level availability across three key macronutrients categories of ‘calories’, ‘digestible protein’ and ‘fat’. To better understand the potential of reduced food chain losses and improved crop yields to close future food deficits, scenario analysis was conducted to 2030 and 2050. Under India’s current self-sufficiency model, our analysis indicates severe shortfalls in availability of all macronutrients across a large proportion (>60%) of the Indian population. The extent of projected shortfalls continues to grow such that, even in ambitious waste reduction and yield scenarios, enhanced domestic production alone will be inadequate in closing the nutrition supply gap. We suggest that to meet SDG2 India will need to take a combined approach of optimising domestic production and increasing its participation in global trade.</p></div

A Secure keyword ordered multiuser searchable encryption framework

Recent trends in information technology have triggered the shift in various sectors from traditional methods of operation and data management to web based solutions. Cloud computing provides the best alternative, providing storage as a service and ensures efficient data operations. Data outsourcing reduces high cost and increases efficiency but it is vulnerable to leakage and manipulation hence rendering it unusable for most of the practical applications. Data encryption makes it safe but limits the scope for search and multiuser access. The model proposed supports efficient data encryption and search over the encrypted data by legitimate users and facilitates multiuser access to the data. Multiuser searchable encryption allows multiple users to access the data in both read and write mode with their distinct keys and facilitates addition and re-invocation of users with less overhead. The proposed scheme is based on encryption of data, keyword generation and search based on bilinear pairing. The system provides a proxy server which manipulates user queries making the system faster and more secure. The search is performed on keyword ordered list which makes the search faster as compared to the traditional methods of comparing trapdoor with keywords associated with the different files.13 page(s

On the sequence of authorization policy transformations

In [2, 3], we proposed a model-based approach to specify the transformation of authorizations based on the principle of minimal change [1] and its application in database systems. Nevertheless, there were some limitations in this approach. Firstly, we could not represent a sequence of transformations. Secondly, default authorizations could not be expressed. In this paper, we propose two high-level formal languages, Ls and Lsd, to specify a sequence of authorization transformations and default authorizations. Our work starts with Ls, a simple, but expressive, language to specify certain sequence of authorization transformations. Furthermore, Lsd has more powerful expressiveness than Ls in the sense that constraints, causal and inherited authorizations, and general default authorizations can be specified.12 page(s

A Dynamic authentication scheme for hierarchical wireless sensor networks

Sensor networks offer economically viable solutions for a wide variety of monitoring applications. In surveillance of critical infrastructure such as airports by sensor networks, security becomes a major concern. To resist against malicious attacks, secure communication between severely resource-constrained sensor nodes is necessary while maintaining scalability and flexibility to topology changes. A robust security solution for such networks must facilitate authentication of sensor nodes and the establishment of secret keys among nodes In this paper, we propose a decentralized authentication and key management framework for hierarchical ad hoc sensor networks. This scheme is light weight and energy aware and reduces the communication overhead.12 page(s