UGC NET JULY 2018 (Computer Science And Applications Paper-II) (Question 46-50)

UGC NET JULY 2018 (Computer Science And Applications Paper-II) (Question 46-50)

Q 46. Which of the following statements are true ?

(a) Three broad categories of Networks are

     (i) Circuit Switched Networks

    (ii) Packet Switched Networks

    (iii) Message Switched Networks

(b) Circuit Switched Network resources need not be reserved during the set up phase.

(c) In packet switching there is no resource allocation for packets.

Code :

1. (a) and (b) only
2. (b) and (c) only
3. (a) and (c) only
4. (a), (b) and (c)

Answer: 3). (a) and (c) only

Q 47. In Challenge-Response authentication the claimant ________.

1. Proves that she knows the secret without revealing it
2. Proves that she doesn’t know the secret
3. Reveals the secret
4. Gives a challenge

Answer: 1). Proves that she knows the secret without revealing it

Reason: Challenge-Response authentication is a computer security protocol in which one party ask a question and another party must provide a valid answer. I.e. she knows the secret without revealing it or will provide the secret when it is asked.

Q 48. Decrypt the message “WTAAD” using the Caesar Cipher with key=15.

1. LIPPS
2. HELLO
3. OLLEH
4. DAATW

Answer: 2). HELLO
Reason: In Ceaser cipher algorithm encryption and decryption takes place. During encryption right shift takes place depending upon the key and in decryption left shift takes place depending on key. In the given question key value is 15 and decryption is asked:
Given message is WTAAD
Left shift 15 on W is H
Left shift 15 on T is E
Left shift 15 on A is L
Left shift 15 on A is L
Left shift 15 on D is O
The decrypted message will HELLO.

Q 49. To guarantee correction of upto t errors, the minimum Hamming distance dmin in a block code must be ________.

1. t+1
2. t−2
3. 2t−1
4. 2t+1

Answer: 4). 2t+1

Q 50. Encrypt the Message “HELLO MY DEARZ” using Transposition Cipher with

1. HLLEO YM AEDRZ
2. EHOLL ZYM RAED
3. ELHL MDOY AZER
4. ELHL DOMY ZAER

Answer: 3). ELHL MDOY AZER 
Reason:
In question encryption of given message using Transposition Cipher with 

Given message is “HELLO MY DEARZ” Now arrange them in group of 4
I.e. HELL OMYD EARZ
i.e. replace the following...

• second character in above format to the first place
• fourth character to the second place
• first character to the third place
• third character to the fourth place.

Encrypted message will be ELHL MDOY AZER.