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  2. 2. Computer SecurityMeans protecting our computer system and theinformation they contains against unwanted access,damage, destruction or modification.
  3. 3. Computer ThreadsMalicious code Is a computer program that perform unauthorized processed an a computer or network There are various kinds of malicious code: i) Virus ii) Trojan horse iii) Logic bomb iv) Trapdoor v) Worm Differences between worm and virus are: WORM VIRUS Operates through the network Spreads through any medium Spread copies of itself as a stand alone Spread copies of itself as a program program that attaches to other program
  4. 4.  A computer infected by a virus, worm or trojan horse has one or more of the following symptoms:  Screen displays unusual message or image  Music or unusual sound plays randomly  Available memory is less than expected  Existing programs and files disappear  Files become corrupted
  5. 5. Hacking Hacking refer to unauthorized access to the computer system by a hacker A hacker is a person who accessed a computer or network illegally A cracker also is someone who accessed a computer or network illegally but has to intend of destroying data, stealing information or other malicious action
  6. 6. Nature threads Computers are threatened by natural or environmental disaster. Be it at home, stores, offices and also automobiles Examples: flood, fire, earthquakes, storms, tornados, excessive heat and inadequate power
  7. 7. Theft Two types of theft i) Computer is used to steal money, goods, information and resources ii) Stealing of computers especially notebook and PDA 3 approaches to prevent theft: i) Prevent access by using locks, smart card or password ii) Prevent portability by restricting the hardware from being moved iii) Detect and guard all exits and record any hardware
  8. 8. Security Measures Security measures are measures taken as a precaution against theft or espionage or sabotage or possible danger or failure Usually we use antivirus, cryptography, firewall and data backup to protect sensitive information
  9. 9. Anti-virus Is a utility program that we use to protect a computer against viruses by identifying and removing computer viruses found in the computer memory, computer storage or incoming e-mails files Examples: Norton Antivirus AVG Kaspersky Bitdefender Nod32
  10. 10. Anti-spyware Is a utility program that we use to protect the computers from spyware Spyware is a software or computer program that is designed secretly record and report an individual’s activities on the Internet Examples: Spybot Search and Destroy Ad-ware Spyware Blaster
  11. 11. Firewall Is a piece of hardware or software which functions in a networked environment to prevent some communications forbidden by security policy We use firewall to prevent hacking (access is the use of a computer or network without permission) Types of firewall SCREENING ROUTERS PROXY GATEWAY GUARD simplest • some what complex • most complex sees only addresses and • sees full text of • sees full text ofservice protocol type communication communication
  12. 12. Backup Is a utility program that makes copy of all files that have been saved onto a disk Backup data is important when original data is corrupted When data corrupted, it is spoilt and cannot be properly used because it has become changed in wrong ways
  13. 13. Cryptography Is a process of transforming plaintext into cipheart then back again Encryption is a process of converting plaintext into cipertext. Decryption is the process of converting ciphertext into plaintext Encryption was used only by intelligence services, militaries and banks. We use cryptography to secure the information and prevent hacking or unauthorized access.
  14. 14. plaintext encrypt ciphertextplaintext decrypt ciphertext
  15. 15. Human aspects The user and also the intruder of a computer system The hardest aspects to give protection The most common problem of human aspect security is the lack of achieving a good information security procedure