Disguise the information in such a way that it meaning make a unintelligible to an authorized person. So we have many way to prevent oth

::Cryptography Terminology

::Cryptography Algorithm

qAsymmetric algorithms P=D(Kd, E(Ke, P))

Slide 16

Slide 17 Slide 17

* a strong encryption algorithm

* a secret key known only to sender / receiver

2) mathematically have: C = EK(P) P = DK(C)

3) assume encryption algorithm is known implies a secure channel to distribute key

Slide 19

Symmetric Cryptography Principles

Symmetric Cryptography Requirements

q

1 ) two requirements for secure use of symmetric encryption:
* a strong encryption algorithm

* a secret key known only to sender / receiver

2) mathematically have: C = EK(P) P = DK(C)

3) assume encryption algorithm is known implies a secure channel to distribute key

Encryption using Asymmetric Cryptography

Methods use in Cryptography Algorithm

¨

Substitution
a) monoalphabetic substitution

- Formed by shifting the letters of the original alphabet

b) polyalphabetic substitution

- Extension of monoalphabetic substitution system

- Using Vigenere Tableau

Transposition

a) unkeyed transposition

- Rearrange letters by using matrix

b) keyed transposition

- Rearrange letters by using matrix where the size of matrix is determined by the length of the key used.

## No comments:

## Post a Comment