1 / 76

NUMBER THEORY

NUMBER THEORY. Chapter 5: Cryptology. Era of Electronic. Electronic communication Electronic Banking. Terminology. Cryptology: Discipline Cryptography: Design & Implementation Cryptoanalysis : Breaking the system. Terminology. Plaintext: secret message

doria
Télécharger la présentation

NUMBER THEORY

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. NUMBER THEORY Chapter 5: Cryptology

  2. Era of Electronic • Electronic communication • Electronic Banking

  3. Terminology • Cryptology: Discipline • Cryptography: Design & Implementation • Cryptoanalysis: Breaking the system

  4. Terminology • Plaintext: secret message • Cipher: method to alter the plaintext • Cybertext: message has been altered

  5. Terminology • encryption/enciphering: process • decryption/deciphering: process

  6. Letter ↔ Integer

  7. Character Cipher Caesar cipher

  8. Exercise

  9. How to decipher?

  10. Exercise

  11. Character Cipher Affine transformation

  12. Complete system of residue!

  13. Exercise:

  14. Secure? • Character cipher is not safe

  15. frequency

  16. Block Cipher Vigenere cipher

  17. Ci=Pi+ki

  18. Exercise • Use the key “SECRET”

  19. Block Cipher Digraphic cipher

  20. Numerical equivalent

More Related