Computer Networ...

Let P be the plaintext, k be the key, E_k be the function to encrypt the plaintext and D_k be the function to decrypt the ciphertext. What is valid function to get the plain text?

Which of the following are used to generate a message digest by the network security

protocols?

P) SHA-256

Q) AES

R) DES

S) MD5

Match the terms with the definition.

If the total relative prime number for integer n from 1 to n is y and n is 23552 then the value of y is _____? 

Consider the following statement.

I. Packet Filter Firewall analyze network traffic at transport layer.

II. Circuit Level Firewall operate at transport and session layer of OSI Model.

Consider an RSA cryptosystem, a participant A uses two prime numbers p and q where p × q = 1247 to generate his public and private keys. The public key of A is e and the private key is d. The value of the public key is 11. The value of the private key d is _____.

Which of the following statements are true?

I. An asymmetric key cryptosystem uses the private and public keys of the receiver

II. A digital signature uses the private and public keys of the sender.

The value of the expression (3⁵³ mod 7) in the range 0 to 7 is _____.

Consider a cyber cafe in which 51 systems are present. All 51 systems want to communicate with each other using symmetric key cryptographic system and the communication should not be decoded by others apart from two systems who are communicating. What is the number of keys required for the systems as a whole to satisfy confidentiality?