Cryptography Overview, TCP/IP and Communication Networks

This is a computer science engineering quiz on cryptography and network security, which includes questions on Cryptography Overview, TCP/IP and Communication Networks.

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Find the number of addresses in a range if the first address is 146.102.29.0 and last address is 146.102.32.255.

1028 1024 578 512

What is the error (if any) in the following representation – 75.45.301.14?

There should be no leading zeros We cannot have more than 4 bytes in an IPv4 address Each byte should be less than or equal to 255 No error

Convert the following dotted-decimal notation to binary notation – 111.56.45.78

01101111 00111000 00101101 01001110 11101111 00111000 00101101 10001110 10000000 00001011 00000011 00011111 10000001 00001011 00001011 11101111

What is the error (if any) in the following representation – 111.56.045.78?

There should be no leading zeros We cannot have more than 4 bytes in an IPv4 address Each byte should be less than or equal to 255 No error

Convert the following binary notation to dotted-decimal notation – 10000001 00001011 00001011 11101111

129.11.11.239 128.11.12.231 127.11.13.244 129.12.1.231

In the elliptic curve group defined by y2= x3- 17x + 16 over real numbers, what is P + Q if P = (0,-4) and Q = (1, 0)?

(15, -56) (-23, -43) (69, 26) (12, -86)

Bob selects E67(2, 3) as the elliptic curve over GF(p). He selects e1 = (2, 22) and d = 4. Then he calculates e2 = d × e1 and the publicly announces the tuple (E, e1, e2). Now, Alice wants to send the plaintext P = (24, 26) to Bob and she selects r = 2. What are C1 and C2?

C1=(35,1) ; C2 =(21,44) C1=(44,21) ; C2 =(1,35) C1=(44,21) ; C2 =(44,21) C1=(21,44); C2 =(35,1)

For the point P (7, 0) defined in the curve E13(1, 1). What is –P?

(7,1) (8,12) (8,1) (7,0)

Consider knapsack that weighs 23 that has been made the weights of the superincreasing series {1, 2, 4, 9, 20, and 38}. Find the ‘n’.

011111 010011 010111 010010

For 1000 nodes in IP level, how many keys would be required?

499000 499500 500500 500000

Which among the following values: 17, 20, 38, and 50, does not have primitive roots in the group G = ?

17 20 38 50

The plaintext message consist of single letters with 5-bit numerical equivalents from (00000)2 to (11001)2. The secret deciphering key is the superincreasing 5-tuple (2, 3, 7, 15, 31), m = 61 and a = 17. Find the ciphertext for the message “WHY”.

C= (148, 143, 50) C= (148, 143, 56) C= (143, 148, 92) C= (148, 132,92)

‘Jitter’ refers to-

Errorless delivery

Variation in the packet arrival time

Timely delivery of message

None of the mentioned

“Meet in the middle attack” is an attack-

Where the timing required for the attack via brute force is drastically reduced

Where the adversary uses 2 or more machines to decrypt thus trying to reduce the time

Where messages are intercepted and then either relayed or substituted with another message

Where cryptanalysis takes lesser time than the brute force decryption

Find the order of group G= <Z7*, x>?