20-11-2012, 02:01 PM
networks security
networksecurity1.ppt (Size: 487 KB / Downloads: 60)
Attacks, Services and Mechanisms
Security Attack: Any action that compromises the security of information.
Security Mechanism: A mechanism that is designed to detect, prevent, or recover from a security attack.
Security Service: A service that enhances the security of data processing systems and information transfers. A security service makes use of one or more security mechanisms.
Goals of security
Confidentiality
Secrecy, privacy
Integrity
Availability
Denial of service
Other goals
Authenticity, non-repudiation, authority, utility, accountability, etc.
Methods of Defense
Encryption
Software controls (access limitations in a data base, in operating system protect each user from other users)
Internal program controls
Operating system controls
Development controls
Hardware controls (e.g. smart cards)
Terminologies
Decryption: The process of retrieving the plaintext back from the ciphertext.
Key: Encryption and decryption usually make use of a key, and the coding method is such that decryption can be performed only by knowing the proper key.