In the last 40 years, “cyberspace” has become a common buzzword. Cyberspace has tremendous potential for human development in many sectors. The security of cyberspace is of utmost importance and poses a great challenge for security experts. So, what is cyberspace security and how is it done? This book, in nine chapters, provides answers to such questions, including modern developments in the mathematical area of the subject.

Chapter 1 covers the basics of cyberspace security, including the strategies of different countries. Chapter 2 collects the mathematical preliminaries needed to understand the rest of the material. Computational preliminaries, including quantum computing and complexity, are addressed in chapter 3. Secret-key and public-key cryptography are covered in chapter 4, which also discusses well-known ciphers, the data encryption standard (DES) and the advanced encryption standard (AES).

Chapter 5 describes the integer factorization-based cryptosystem and its attacks in the era of quantum computing. Cryptosystems based on the discrete log problem are described in chapter 6, including quantum attacks on such systems. Next, chapter 7 discusses elliptic-curve-based cryptosystems and quantum attacks. The cryptosystems presented in chapters 5, 6, and 7 are not quantum safe. However, post-quantum cryptosystems such as coding theory cryptosystems and lattice-based cryptosystems, which are safe even if quantum computers are there, are discussed in chapter 8. Even quantum cryptosystems and deoxyribonucleic acid (DNA) biological systems are touched on here. Finally, chapter 9 discusses malware. Each chapter concludes with notes, further reading, and references. Many sections include a problem set and all sections include examples.

This is a nice textbook for students who want a quick overview of modern cryptosystems. It will also be useful for researchers and professionals working in cybersecurity. The book is easy to read. I strongly recommend it.