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. Cryptography is the art of writing something secretly. Cryptographic algorithms are the basis of carefree transactions over the internet today. Confidential information of a government or private agency or department is secured by cryptography. From doing secure communication to transferring information of national importance, cryptographic algorithms play the sole role in confidentiality. Cryptography is basically a mathematical model used for hiding confidential information. With the advancement in internet technologies and reliance of everyone on the use of internet in day-to-day life, it has become of utmost importance to hide the confidential information shared over the internet in a form that cannot be read by an intruder.