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WorksheetsEmbedded Security Quiz No 4
Total questions: 15
Worksheet time: 35mins
Choose the wrong statement from the following for the Feistel cipher.
It has substitution & permutation network
Data is divided into two halves such as L & R
Round keys would be used in each round
Maximum round of operation is 16
Consider the diagram. The input data is 16’b1111111110101010. The function F is the combination of R with rotation of a single bit to left and XOR operation with K where K is 8’hAA. Find out the resultant of this Feistel cipher.
16’hFF00
16’hF0F0
16’hAA00
16’h00AA
Consider, the Feistel structure takes the input of 64 bits for encryption with rounds of operation R = 1. A synchronous clock has been provided through which the Feistel operations have been performed. Hence, how many clock cycles were required to cipher the entire input data when blocking operator is being used in the scheme?
1
2
4
8
What is the maximum number of input bits for AES?
128
192
256
512
How many bytes of keys were required for AES – 128 bit architecture?
160
176
200
192
Find the logic/logics for the operation of W = K * 17
W = (K >> 2) | (K >>3) | (K >> 1) | (K >> 1) | (K)
W = (K << 2) | (K << 3) | (K << 1) | (K << 1) | (K)
W = (K << 3) | (K << 5) | (K)
W = (K) | (K << 4)
Consider the variables A & B where A = 8’h83 & B = 8’h57. Perform modulo 2 addition and find the correct answer from the options given below.
A4
18
E1
D4
What is the advantage of RC5 over Feistel cipher?
It operates two blocks at a time
It has 256 rounds of operations
Maximum number of input bit is 64
It has primitive computer operations
How many sub-keys were required in RC5 cipher when the round R = 1?
1
2
3
4
Which is the biggest disadvantage of the symmetric Encryption?
More complex and therefore more time-consuming calculations
Problem of the secure transmission of the secret key
Less secure encryption function
Inverse operations are difficult
RC5 encryption uses right shift and decryption uses left shift. Say True or False?
True
False
What is the frequency of oscillation of a Ring Oscillator?
1/2tpn
1/2tn
1/Tn
1/tn
the frequency of oscillation affected by the increase in temperature of a ring oscillator?
Frequency increases with increase in temperature
Frequency decreases with increase in temperature
Frequency remains the same
Frequency increases first and then decreases
To increase the frequency of oscillation, which of the following can be utilized?
(a) Applied power supply voltage may be increased.
(b) Reduce the number of inverter stages.
Only (a)
Only (b)
Both (a) & (b)
Neither (a) nor (b)
Which of the following is the example for Feistel structure?
Advanced Encryption Standard
International Data Encryption Standard
Data Encryption Standard
Magma cipher
