This book is based on the author&39;s 18 years of teaching and research experience.It covers the fundamental principles in Computer and Internet security,including software security, hardware security, network security, web security, and cryptography. Its goal is to help readers understand how variousattacks work, what their fundamental causes are,how to defend against them, and how various defense mechanisms work.The book can be used as a textbook for undergraduate and graduatecourses. Over 80 universities and colleges adopted the first editionof this book within the first 15 months since it was published in late 2017.The author strongly believes in learning by doing, sothe book takes a hands-on approach.For each security principle, the book uses a series of hands-on activitiesto help explain the principle; readers can touch, play with, and experiment with theprinciple, instead of just reading about it.For instance, if a security principle involves an attack,the book guides readers to actually launch the attack (in acontained environment).