What Is Computer Security?

Computer Security is a branch of technology known as information security as applied to computers. Information security means protecting information and information systems from unauthorized access, use, disclosure, disruption, modification, or destruction. The objective of computer security varies and can include protection of information from theft or corruption, or the preservation of availability, as defined in the security policy.

Technological and managerial procedures applied to computer systems to ensure the availability, integrity and confidentiality of information managed by the computer system. Computer security imposes requirements on computers that are different from most system requirements because they often take the form of constraints on what computers are not supposed to do.

Typical approaches to improving computer security can include the following:
-Physically limit access to computers to only those who will not compromise security.
- Hardware mechanisms that impose rules on computer programs, thus avoiding depending on computer programs for computer security.
- Operating system mechanisms that impose rules on programs to avoid trusting computer programs.
- Programming strategies to make computer programs dependable and resist subversion.

Computer Security has three Layers:

1- Hacking:
Unauthorized use or attempts to circumvent or bypass the security mechanisms of an information system or network.
Computer hacking always involves some degree of infringement on the privacy of others or damage to computer-based property such as files, web pages or software. The impact of computer hacking varies from simply being simply invasive and annoying to illegal.

2- Cracking:
The act of breaking into a computer system.
Software Cracking is the modification of software to remove protection methods: copy prevention, trial/demo version, serial number, hardware key, CD check or software annoyances like nag screens and adware. The most common software crack is the modification of an application's binary to cause or prevent a specific key branch in the program's execution.

3- Phreaking:
The art and science of cracking the phone network.