Network Security
Q22.
A sender S sends a message m to receiver R, which is digitally signed by S with its private key. In this scenario, one or more of the following security violations can take place. I. S can launch a birthday attack to replace m with a fraudulent message. II. A third party attacker can launch a birthday attack to replace m with a fraudulent message III. R can launch a birthday attack to replace m with a fraudulent message. Which of the following are possible security violations?Q23.
Anarkali digitally signs a message and sends it to Salim. Verification of the signature by Salim requiresQ24.
In a system an RSA algorithm with p=5 and q=11, is implemented for data security. What is the value of the decryption key if the value of the encryption key is 27?Q25.
Using public key cryptography, X adds a digital signature \sigma to message M, encrypts \lt M, \sigma \gt, and sends it to Y, where it is decrypted. Which one of the following sequences of keys is used for the operations?Q27.
What will be the cipher text produced by the following cipher function for the plain text ISRO with key k=7. [ Consider 'A'=0, 'B'=1,....'Z'=25] C_{k} (M) = (kM + 13) \mod 26Q28.
Suppose that everyone in a group of N people wants to communicate secretly with the N-1 others using symmetric key cryptographic system. The communication between any two persons should not be decodable by the others in the group. The number of keys required in the system as a whole to satisfy the confidentiality requirement isQ29.
Consider that B wants to send a message m that is digitally signed to A. Let the pair of private and public keys for A and B be denoted by K_{x}^{-} and K_{x}^{+} for x = A,B, respectively. Let K_{x}(m) represent the operation of encrypting m with a key K_{x} and H(m) represent the message digest. Which one of the following indicates the CORRECT way of sending the message m along with the digital signature to A?Q30.
In a RSA cryptosystem a participant A uses two prime numbers p=13 and q=17 to generate her public and private keys. If the public key of A is 35. Then the private key of A is __________.