What is computer security?

What is computer security? For some it is controlling access to hardware, software and data of a computerized system

A large measure of computer security is simply keeping the computer system's information secure. In broader terms, computer security can be thought of as the protection of the computer and its resources against accidental or intentional disclosure of confidential data, unlawful modification of data or programs, the destruction of data, software or hardware. It includes the denial of use of one's computer facilities for criminal activities including computer related fraud and blackmail.

Computer security involves the elimination of weaknesses or vulnerabilities that might be exploited to cause loss or harm.

Computer Security - the protection of the computer resources against accidental or intentional disclosure of confidential data, unlawful modification of data or programs, the destruction of data, software or hardware, and the denial of one's own computer facilities irrespective of the method together with such criminal activities including computer related fraud and blackmail.[Palmer]

• exposure - form of possible loss or harm in a computing system.
• vulnerability - weakness in the security system that might be exploited to cause a loss or harm.
• threats - circumstances that have the potential to cause loss or harm.
• control - protective measure that reduces a vulnerability.

Three main points of computer security:

• secrecy - limiting who can access assets of a computer system.
• integrity - limiting who can modify assets of a computer system.
• availability - allowing authorized users access to assets.

Four kinds of threats to the security of a computer system:

• interruption - asset of system becomes lost or unavailable or unusable.
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• interception - some unauthorized party has gained access to an asset.
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• modification - some unauthorized party tampers with an asset.
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• fabrication - some unauthorized party might fabricate counterfeit objects for a computer system.
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Network Security Issues

• sharing of resources complexity of system
• unknown perimeter (linked networks) unknown path
• many points of attack

Security Exposures

• privacy data integrity
• authenticity covert channels

Solutions

• encryption
• access control
• automatic call back
• node authentication
• differentiated access rights
• user authentication
• passwords and passphrases
• challenge-response systems
• token or smart cards
• exchange of secret protocol
• biometric (personal characteristics)

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