GATE CSE
Computer Networks
Network Security
Previous Years Questions

## Marks 1

The value of 351 mod 5 is_________.
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 securi...
Anarkali digitally signs a message and sends it to Salim. Verification of the signature by Salim requires
Suppose that everyone in a group of N people wants to communicate secretly with the N - 1 others using symmetric key cryptographic system. The communi...
Which one of the following are used to generate a message digest by the network security protocols? (P) RSA (Q) SHA-1 (R) DES (S) MD5
Using public key cryptography, X adds a digital signature σ to message M, encrypts, and sends it to Y, where it is decrypted. Which one of the followi...
A layer-4 firewall (a device that can look at all protocol headers up to the transport layer) CANNOT
Consider the following two statements: i. A hash function (these are often used for computing digital signatures) is an injective function. ii. encr...
The minimum positive integer p such that (3p modulo 17) = 1 is
Exponentiation is a heavily used operation in public key cryptography. Which of the following options is the tightest upper bound on the number of mul...
A sender is employing public key Cryptography to send a secret message to a receiver. Which one of the following statement is true?

## Marks 2

In an RSA cryptosystem, the value of the public modulus parameter n is 3007. If it is also known that $$\varphi$$(n) = 2880, where $$\varphi$$() den...
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 $$K_x^ -$$...
In the RSA public key cryptosystem, the private and public keys are (e, n) and (d, n) respectively, where n = p$$\times$$q and p and q are large pri...
The total number of keys required for a set of n individuals to be able to communicate with each other using secret key and public key crypto-systems,...
Suppose that two parties A and B wish to setup a common secret key (D - H key) between themselves using the Diffie-Hellman key exchange technique. The...
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