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Introduction to Security in Computing. 01204427 Computer and Network Security Semester 1, 2011. Lecture #01. What’s about Security. Why to secure something? Valuable assets to protect How to secure? Place in a safe place Guarding How strong of protection? May implement several layers
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Introduction to Security in Computing 01204427 Computer and Network Security Semester 1, 2011 Lecture #01
What’s about Security • Why to secure something? • Valuable assets to protect • How to secure? • Place in a safe place • Guarding • How strong of protection? • May implement several layers • May be complex locks system • May need multiple parties to grant access
Principle of Adequate Protection Computer items must be protected to a degree consistent with their value
Security in Computing System • Computing System • Collection of • HW • SW • Storage • Data • People
Threats, Controls, and Vulnerabilities • A threat is blocked by control of a vulnerability
Security Goal: Confidentiality • Only authorized people or system can access protected data • Ensuring the confidentiality can be difficult! • More to concern • Access : a single bit or the whole collection? • Disclose to other parties prohibit?
Security Goal: Integrity • Several meanings • Precise • Accurate • Unmodified • Modified in acceptable way • Consistent • May cover two or more of above properties
Security Goal: Availability • Several properties • Present in a usable form • Enough capacity to meet the service’s needs • Bounded waiting time • Completed services in an acceptable period of time • System is well available if :- • Timely response to a request • Generalized fairly allocate resources • Fault tolerance (graceful cessation instead of crash or abrupt) • Easily to be used • Concurrency is controlled (simultaneous, deadlock management, exclusive access)
Some of software modifications • Logic Bomb • Trojan • Virus • Trapdoor • Information Leaks
Computer Criminal • Armatures • Crackers • Career Criminals • Terrorists
Method of Defense • Prevent • Blocking the attack • Closing the vulnerability • Deter • Making the attack harder • Deflect • Making another target more attractive • Detect • Discover real-time or off-line • Recover • From its effects