The book will introduce readers to the broader concept of cryptography and its allied areas. Introduction to various cryptographic protocols such as symmetric and asymmetric encryption algorithms are provided in this book. New techniques such as blockchain and lightweight cryptography are also discussed in this book. The book additionally focuses on the musical cryptography concept and many new algorithms to secure communication are shown to be achieved using Indian music. Integer factorization is also discussed in this book with a plausible algorithm to break it in polynomial time. The book should be found useful to advanced undergraduate and post-graduate students, researchers and practitioners of computing science.