Network Security Unit I

Which technique is used in the following

a) a graduate student uses watermark to protect her thesis.

b) A student writes the answer on a small piece of paper, rolls up the paper and inserts it in a ball pen and passes pen to other student.

• Cryptography

• Substitution Cipher

• Stenography

• None of these

Write three important goals of Security.

A cipher ________ replaces one symbol by another.

The plaintext is hello and ciphertext is KHOOR.

Which cipher is this?

• Monoalphabetic

• Polyalphabetic

• Caesar

• Hill Cipher

What is the ciphertext for hello using key 15.

• XUBBE

• USZZC

• WTAAD

• HELLO

Which security mechanism is provided when

A school demands student identification and a password to let students log onto the school server.

After how many rounds DES is actually secure?

• 16

• 7

• 10

• 8

If Atish cannot access computer system,it means that the principle of ____________ is violated.

• Confidentiality

• Availability

• Integration

• Access Control

Snooping and Traffic analysis are which type of attack?

• Is not attack

• Active

• Passive

• Both Passive and active

In Transposition cipher involves

• Replacement of blocks of text

• Combination with alphabetical key

• Strictly row to column replacement

• None of the above