1. Computer Security (CS4800)
Survey
Prepared by Dr. Lamiaa Elshenawy

2. 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

3. Computer security concepts
Confidentiality
Data ----Privacy
Integrity
Data----System
Availability
Authenticity
Accountability
- CIA triad

4. OSI security architecture
Security Attack
Security Mechanism
Security Service

5. 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

6. Security Services Security Services Authentication Access control
Data confidentiality
Data Integrity
Nonrepudiation
Availability

7. Authentication Exchange
Security Mechanism
Security mechanism
Encipherment
Digital signature
Access control
Data Integrity
Authentication Exchange
Traffic padding
Routing Control
Notarization

8. 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

9. Symmetric Cipher Model
1- Cryptography (enciphering)
- Cryptology
2- Cryptanalysis (deciphering)
- Cryptanalyst

10. 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

11. Symmetric Cipher Techniques
- Rotor machines
- Steganography
Character marking
Invisible ink
Pin puncture
Type writer correction ribbon

12. Thank you for your attention