Understanding the RSA algorithm

With the emerging importance of cybersecurity, it will be beneficial for a wide community to understand some of the fundamental security mechanisms. The RSA algorithm is one of the essential algorithms used in public-key cryptosystems. Understanding the RSA algorithm requires knowledge regarding number theory, modular arithmetic, etc., which is often beyond the knowledge pool of many beginners in cybersecurity. In this work, we provide an intuitive and onion-peeling style introduction to the RSA algorithm, in which we assume that readers will only have a basic background in mathematics and cybersecurity. Started from three essential goals of public-key cryptosystems, we explained step-by-step how the RSA algorithm achieved these goals. We also used a toy example to further help readers to understand the algorithm from a practical perspective.