Tuesday, July 31, 2007

class note

prim number is divided by itself or 1
relativley prime
modualar
find the additive inverse 22 mod 47
find the additive inverse 12 mod 100

multiplicative inverse of
9 mod (10)
17 mod (23)

Homework:
from the net research: ECB electronic code book - CBC - one round of DES - RSA

Tuesday, July 24, 2007

class excersie

Vigenere cipher
the gold is buried under the plane tree
6-9-12-15-22

A B C D EFGHIJKLMNOPQRSTUVWXYZ

Class notes

Security in IT Network:


  • response
  • eduction
  • authentication
  • non-repudution
  • disastor recovery
  • threats
  • attacks
  • integrity
  • firewall
  • policy
  • risk management
  • physical security

type of cryptography:

Classic Cryptography

Monoalphabetic Substitution (taken in the class)