Please recommend a few introductory books on network security.
The books on cybersecurity were recommended as follows: Computer Network Security (Second edition): This book is one of the classic textbooks in the field of computer network security. It covers network attacks and defenses, vulnerability scanning and penetration testing, security strategies and risk management, and other aspects. 2.<<Technology and applications of digital signatures>>(Second edition): This book introduced the basic principles, application fields, and implementation techniques of digital signatures. It is very helpful for beginners to understand the principles and techniques of digital signatures. 3 "The authoritative guide to Web application security"(second edition): This book is a comprehensive and in-depth guide to web application security, covering the basic knowledge of Web application security, attack methods and preventive measures. It is suitable for beginners and readers with some Web security experience. 4 "Cryptology Basics"(second edition): This book introduced the basics of encryption, including encryption algorithms, symmetrical encryption and symmetrical encryption, and the Hash function. It is suitable for beginners to understand the basic concepts and techniques of encryption. Introduction to Network Security (Second edition): This book introduced the basic concepts of network security, threats and attack methods, as well as network security management and preventive measures. It is suitable for beginners to understand the basic knowledge of network security.