Illustrate using diagram and briefly describe DES Algorithm

What are the problems with DES?

Whey there is a Need for Public$-$key cipher?

What are the three misconceptions about public$-$key cryptography?

What are the Requirements of Public$-$key cryptography?

Compare between symmetric key and asymmetric key

Use RSA public cryptography to process the following encryption:

$P=7,q=17$ This gives $n=,y=$

We choose $e=5$ which satisfies

We calculate $d$ such the $de$ mod dotsdotsdots$=$

$q,$

$q,$

$q,$

$q,$

$q,$

$q,$

The first available value of $d$ is

Therefore, the public key $K_B=(,)$ and the private Key $K_v=(,).$

For the plaintext $m=4$

The ciphertext is given by

The plaintext is then decrypted by

$q,$

Whey we need Combined Encryption Technique?