Computer Security (CS4800) Survey Prepared by Dr. Lamiaa Elshenawy
Survey Book (CRYPTOGRAPHY AND NETWORK SECURITY PRINCIPLES AND PRACTICE, 5th edition, William Stallings) Computer security concepts OSI security architecture 1- Security Attacks 2- Security Services 3- Security Mechanisms Access Control Classical Encryption Techniques
Computer security concepts Confidentiality Data ----Privacy Integrity Data----System Availability Authenticity Accountability - CIA triad
OSI security architecture Security Attack Security Mechanism Security Service
Security Attack Security Attack Passive attacks Active attacks - not detect - easy prevent - detect - not prevent 1- Release of message contents 2- traffic analysis 1- masquerade 2- Replay 3- modification of message 4- denial of service
Security Services Security Services Authentication Access control Data confidentiality Data Integrity Nonrepudiation Availability
Authentication Exchange Security Mechanism Security mechanism Encipherment Digital signature Access control Data Integrity Authentication Exchange Traffic padding Routing Control Notarization
Symmetric Cipher Model Plaintext input 1- encryption algorithm 2- secret key Encryption Cipher text output Cipher text input 1- Decryption algorithm 2- secret key Decryption Plaintext output
Symmetric Cipher Model 1- Cryptography (enciphering) - Cryptology 2- Cryptanalysis (deciphering) - Cryptanalyst
Symmetric Cipher Techniques - Substitution techniques Caesar Cipher Monoalphabetic Ciphers Playfair Cipher Hill Cipher Polyalphabetic Ciphers (Vigenère cipher –Vernam cipher) One-Time Pad - Transposition techniques Rail fence
Symmetric Cipher Techniques - Rotor machines - Steganography Character marking Invisible ink Pin puncture Type writer correction ribbon
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