1. What do you mean by DNS and describe the main sections of DNS in detail?
2. With a neat and suitable diagram describe the basic model of FTP?
3. What is public key cryptography and describe RSA in detail with suitable example.
4. Describe different kinds of substitution techniques.
5.a) SMTP, FTP and HTTP are protocols to transfer messages from one point to another. Describe their usage and compare and contrast them.
b. Write detailed notes on HTTP Request and Response messages.
6. Describe about SMTP in detail.
7.a) Make use of the following encryption algorithm to encrypt message,
a. Replace each character with its ASCII code
b. Add a 0 bit at the left to make each character 8 bits long
c. Swap the first 4 bits with the last 4 bits.
d. Replace every 4 bits with its hexadecimal equivalent, Determine is the key in this method
b. Using RSA algorithm, encrypt and decrypt message “BE” with key pairs(3,15) and (5,15).