Chapter 4: Security Architecture and Design

Computer Security:

• Computer security means different things to different people.
• Information security should consist of the three main attributes: 
• Availability: prevention of loss from access to data and resources
• Integrity: prevention of unauthorized modification of data and resources
• Confidentiality: prevention of unauthorized disclosure of data and resources

System Architecture:

• What is an architecture?
• An architecture is a tool used to conceptually understand structure and behavior of a complex entity through different views (Harris, 300). 
• What is an architecture description?
• It is a formal description and representation of a system, components that make it up, interactions and interdependencies between those components, and relationships to the environment (Harris, 300).
• An architecture is a high level overview of the overall process of system development. The architecture is what needs to be understood before we can design and develop. In the architecture level we ask the following questions:
• Why are we building this system?
• Who is going to use it and why?
• How is it going to be used?
• What environment will it work within?
• What type of security and protection is required?
• What does it need to be able to communicate with?
• The answers to the questions above will outline the main goals the system must achieve and they help to construct the system at an abstract level. 
• Why is involved in the system phase?
• Gathering system requirement specifications.
• Use modeling languages to establish how system will accomplish design goals (e.g. required functionality, compatibility, fault tolerance, extensibility, security, usability, and maintainability).
• Modeling language is commonly graphical to help visualize the system from a static structural view and dynamic behavioral view. 
• What is involved in the development phase?
• Individual programmers are assigned a part of the system they are responsible fore.
• The coding of the software begins and the creation of the hardware starts. 
• What is a system?
• A system can be an individual computer, application, set of subsystems, set of computers, or a set of network made up of computers and applications. 
• It can be simplistic such as a single-user operating system for a specific task or it can be complex such as a distributed environment or very focused subsystems.