Security Issues in Communication Systems

1. Security Issues in Communication Systems Advanced Communication Services Seminar 2003 Thomas Bürgstein Mentor: Dr. Stephan Rupp Seminar ACS - Security Issues in Communication Systems

2. Overview • Need of Security • Threats in Communication Systems • Functional Security • Internet Security • Firewall • Virtual Private Networks • Cryptography • Conclusion Seminar ACS - Security Issues in Communication Systems

3. I. Need of Security • Damage • Users most dangerous part • Privacy • Control of data flow • Monitoring data • Protection of the system • Manipulating • Unauthorized access • Definition: Virtual secure system Seminar ACS - Security Issues in Communication Systems

4. II. Threats in Communication Systems • Local threats • Thefts • Spying • Network threats • Manipulating data via the network • Central IT threats • Unauthorized access to a network Seminar ACS - Security Issues in Communication Systems

5. III. Functional Security Main point: deal with threats To obtain the right level of security: • Needed requirements? Seminar ACS - Security Issues in Communication Systems

6. IV. Internet Security • Attacks: direct or indirect? • Malicious code Virus, Worm, Hoax, Trojan • Anti-virus programs Scanner, Checker, Blocker Seminar ACS - Security Issues in Communication Systems

7. V. Firewall • Filter • Packet Filter • Port Filter • Session Level Firewall • Application Level Firewall Seminar ACS - Security Issues in Communication Systems

8. VI. Virtual Private Networks • Secure communication via a untrustworthy network • Comparison: money lorry • Types • Site-to-site VPN • Remote access VPN • Extranet Seminar ACS - Security Issues in Communication Systems

9. VII. Cryptography plaintext cipher text plaintext decryption key encryption key possible intruder passive: active: monitors manipulates Seminar ACS - Security Issues in Communication Systems

10. VII. Cryptography Present concepts: P-box Transposition S-box Substitution Seminar ACS - Security Issues in Communication Systems

11. VII. Cryptography Symmetric Cryptography: under secret random number generation of the key transmission of key encryption decryption transmission of cipher text Seminar ACS - Security Issues in Communication Systems

12. VII. Cryptography under secret Asymmetric Cryptography: random number transmission of encryption key generation of the keys decryption key encryption decryption transmission of cipher text Seminar ACS - Security Issues in Communication Systems

13. VII. Cryptography • Key distribution problem Milestone: Public key cryptography Concepts: Logarithm (Diffie/Hellmann) Factorizing (RSA) Seminar ACS - Security Issues in Communication Systems

14. VII. Cryptography Digital signature and certification: under secret transmission private key A public key A encryption decryption sender A receiver B decryption encryption under secret public key B private key B transmission certification system Seminar ACS - Security Issues in Communication Systems

15. VIII. Conclusion • Requirement of a closer look on security • Evaluation of needs and threats necessary • Most insecure part of the system: its users • Training necessary • On-going process in security • Enhancement of tools necessary Seminar ACS - Security Issues in Communication Systems