Network Defence

what is encryption in the context of network security?

• Authenticating users based on their unique characteristics

• Hiding the true source of network traffic

• Scanning network traffic of malicious patterns

• Converting plaintext data into cipertext to prevent unauthorized access

Which of the following is NOT a security service defined in OSI security architecture?

• Confidentiality
  

• Integrity

• Availability
  

• Compression

In a Caesar cipher, if the key is 3, what is the cipher text of "CYBER"?

• KHOOR

• FBEHU

• GDKKN

• JGNNQ

In the symmetric cipher model, which key is used for decryption?

• Same key as encryption

• No key is used

• Public key

• A different key from encryption

Which of these is NOT a substitution cipher?

• Playfair Cipher

• Vigenère Cipher

• Rail Fence Cipher

• Hill Cipher

Simplified DES (SDES) operates on a block size of:

• 12 bits

• 8 bits

• 14 bits

• 4 bits

what is the purpose of access control mechanisms in network security?

• To prevent unauthorized users from accessing sensitive resources

• To increase network speed and reduce latency

• To monitor network traffic for performance optimization

• To create backups of user data automatically

An algorithm in encryption is called______________?

• Algorithm

• ciper

• procedure

• module

what is the common name for the caesar ciper, a basic encryption technique?

• Transposition cipher

• Asymmetric cipher

• Shift cipher

• symmetric cipher

An example of poly alphabetic substitution is_________________?

• P-box

• S-box

• Caesar cipher

• Vigenere cipher