Security Attacks

• Virus - Reproduces itself by attaching to other executable files.
• Worm - Self-reproducing program. Creates copies of itself. Worms that spread using e-mail address books are often called viruses.
• DoS- Denial of Service
• Trojan Horse - Comes with other software.
• Logic Bomb - Dormant until an event triggers it (Date, user action, random trigger, etc.).

1. Security Attack: Any action that compromises the security of information owned by an organization.
2. Security Mechanism: A process that is designed to detect, prevent or recover from a security attack.
3. Security Service: A processing or communication service that enhance the security of data processing systems to counter security attacks and make use of one or more counter security attacks and make use of one or more security mechanisms is called a ‘Security Service’.

Conventional Encryption:

1. Threat: Threat is a possible danger that might exploit vulnerability.
2. Attack: An intelligent act that is a deliberate attempt (especially in the sense of a method or technique) to evade security services and violet the security policy of system. It is an assault on system security that derives from an intelligent threat.
3. Plain-text: This is the original intelligible message or data that is fed into the algorithm as input.
4. Cipher-text: This is the scrambled message produced as output. The cipher-text is an apparently random stream of data and as it stands is unintelligible.

Types of Security Attacks:

1. Passive Attack: It attempts to learn or make use of information from the system but does not affect system resources.
2. Active Attack: It attempts to alter system resources or affect their operation.