Computer Security, Second Edition aims to present different ideas and practices that promote the prevention of attacks on computer systems and data being compromised. The book is divided into five parts. Part I covers the important elements of computer security and case histories of computer-related crimes. Part II discusses the organizations and models for the protection of information. Part III talks about the physical security involved and access control involved in data protection. Part IV deals with the different measures employed to promote security in the communication between computers. Part V explains systems security, its access control, and integrity. The text is recommended for people involved in the promotion of computer security, especially programmers and IT practitioners, in institutions where computer-processed information is crucial and must be protected.