This book contains best selected research papers presented at ICTCS 2021: Sixth International Conference on Information and Communication Technology for Competitive Strategies. The conference will be held at Jaipur, Rajasthan, India, during December 17-18, 2021. The book covers state-of-the-art as well as emerging topics pertaining to ICT and effective strategies for its implementation for engineering and managerial applications. This book contains papers mainly focused on ICT for computation, algorithms and data analytics, and IT security. The book is presented in two volumes.