The practice of protecting information by eliminating or reducing information risks is termed as information security. It is an important constituent of information risk management. It is primarily concerned with the prevention or reduction of the probability of inappropriate access, disclosure, use, disruption, destruction, modification, and recording. The key concepts related to information security are confidentiality, integrity and availability. Confidentiality ensures that information is not disclosed to unauthorized individuals or entities. Maintaining the accuracy and completeness of data over its entire lifecycle is termed as data integrity. Availability of information involves making it available whenever it is needed. This book is compiled in such a manner, that it will provide in-depth knowledge about the theory and principles of information security. It unfolds the innovative aspects of this field which will be crucial for the holistic understanding of the subject matter. This book will serve as a valuable source of reference for those interested in this field.