The document discusses the evolution and current state of cryptography, detailing both symmetric and asymmetric key systems and their applications in securing digital data. It emphasizes the importance of cryptography for maintaining privacy over the internet and introduces quantum cryptography as a novel approach. The document also highlights the vulnerabilities of traditional systems, particularly concerning brute force attacks.

1. Security Systems for Digital Data Big Brother is watching YOU Bernhard Hofer 03/10/2008 CIST 3100 - Organizations, Applications & Technology

2. Table of contents History and Terminology Cryptography nowadays and Encrypting Digital Data Big Brother www The Future (quantum cryptography) Question time

3. Beginning of cryptography Egypt‘s Old Kingdom (4500+ years ago) non-standard hieroglyphs The Greeks of Classical times The SCYTALE, used by Spartan military enlarge image

4. Page H E L P M E I A M … wood cylinder strip of paper

5. Terminology (I) c r y p t o g r a p h y kryptós, „hidden“ graphéin, „to write“ „ secret writing“

6. Terminology (II) Hello, this is my first english pres at UNO … plaintext (ordinary information) encryption (converting plaintext) decryption (reverse process) H?$% /&!!““= )(/&%ded die=? 30((&% ?$$?) … ciphertext (unreadable plaintext) cipher key +

7. Table of contents History and Terminology Cryptography nowadays and Encrypting Digital Data Big Brother www The Future (quantum cryptography) Question time

8. Cryptography nowadays (I) “ Cryptography is about communication in the presence of adversaries.” Ronald Rivest , "Cryptography" From the Handbook of Theoretical Computer Science, edited by J. van Leeuwen, Elsevier Science Publishers B.V., 1990

9. Symmetric key system (private key) … sender and receiver share the same key (for encryption and decryption) … like the wind (very fast) … 2 different kinds (block and stream ciphers) … Examples: D(A)ES, RC4, MD5, hash Cryptography nowadays (II)

10. Asymmetric key system (public key) … founded 1976 by Diffie and Hellman … 2 keys (same lenght) : 1 public and 1 private … both are different but related … slower than symmetric key methods Cryptography nowadays (III)

11. Cryptography nowadays (IV) Key Server in a so called Trust Center Player 1 Player 2 public key private key … delivering message !! Authentication Problem !! Player 2 doesn‘t know, who sent the message!?! Everybody knows the public key from Player 2! … wants to deliver a SECURE message encrypting … decrypting …

12. Cryptography nowadays (VI) Key Server in a so called Trust Center Player 1 Player 2 public key private key … delivering message !! Confidentiality Problem !! Player 2 knows, who sent the message! But: Everybody could decrypt the message from Player 1! continue pres. … wants to deliver a SECURE message encrypting … decrypting …

13. Asymmetric key system (public key) … full security, if process repeated twice … operational area : Combination of the symmetric and asymmectric … Examples: RSA, DSA, SSL, SSL2, … Cryptography nowadays (VIII)

14. Table of contents History and Terminology Cryptography nowadays and Encrypting Digital Data Big Brother www The Future (quantum cryptography) Question time

15. The internet … local structure … none secure, open information system … private, public and economic player … cryptography is the only way for privacy protection over the world wide web! Big Brother www (I)

16. Requirements for secure interaction … availability … authentification … confidentiality … integrity … commitment Big Brother www (II)

17. Useful applications … PGP (Pretty Good Privacy) RSA, IDEA founded 1991 by Phil Zimmermann … confidential certificates digital signature for online banking … SSL (Secure Socket Layer … https://) founded by Netscape, cryptography for web pages Big Brother www (III)

18. The one and only security hole is Nothing and/ore nobody could save you against Brute Force Attacks ;-) !! YOUR PASSWORD !! Big Brother www (IV)

19. cost increases per power (10.000 $, 100.000 $, 1.000.000 $, …) Key length in Bit Codebreaking timetable

20. Table of contents History and Terminology Cryptography nowadays and Encrypting Digital Data Big Brother www The Future (quantum cryptography) Question time

21. In princible … … it is a old school symmetric encryption … nothing else as a key distributer … it isn‘t based on mathematical … but on the physics of information Quantum cryptography (I)

22. In action … … first implemented between the BA CA and the Vienna City-Hall over a 1.500m FDDA (fibre optics) cabel in April 2004 by Anton Zeilinger … Quantum cryptography (II)

23. Table of contents History and Terminology Cryptography nowadays and Encrypting Digital Data Big Brother www The Future (quantum cryptography) Question time

24. … for your attention!! Bernhard Hofer CIST 3100 - Organizations, Applications & Technology Thank you...