1. PRNGs are derived through algorithms.
a) True
b) False
Explanation: PRNGs are derived through algorithms. These algorithms are deterministic and therefore produce sequences of numbers that are not statistically random. Thus we should choose an algorithm which provides a high degree of randomness.
2. TRNGs take in an input which is referred to as
a) random variable
b) external variable
c) entropy source
d) bit stream
Explanation: TRNGs use an input known as “entropy source” which is an input source that is effectively random.
3. PRNGs take in an input which is referred to as
a) bit stream
b) seed
c) entropy source
d) external variable
Explanation: PRNGs use an input known as “seed”. The seed is usually generated using a TRNG.
4. Which of the following produces an output of fixed length?
a) PRNG
b) TRNG
c) PRF
d) All of the mentioned
Explanation: Only PRFs produce an output of fixed length. TRNGs and PRNGs have open ended outputs.
5. Which of the following a is NOT a check for randomness?
a) Uniformity
b) Scalability
c) Consistency
d) All of the mentioned
Explanation: Uniformity, Scalability and Consistency are all checks for randomness of a PRNG.
6. The property that there should be equally likely number of 1s and 0s in a Pseudo Random Number sequence is
a) Scalability
b) Uniformity
c) Stability
d) Consistency
Explanation: This is the property of Uniformity.
7. The property that any extracted subsequence should pass the test for randomness is
a) Scalability
b) Uniformity
c) Stability
d) Consistency
Explanation: Scalability is the property where any extracted subsequence should pass the test for randomness.
8. Using the Linear Congruential Method (LCM), for a=7, c=0 and m=32. The period is
a) 13
b) 4
c) 11
d) 7
Explanation: The sequence generated is {7,17,23,1,7..}. Thus the period is 4.
9. Using the Linear Congruential Method, for a=5, c=0 and m=32. The period is
a) 8
b) 4
c) 9
d) 11
Explanation: The sequence generated is {2,25,29,17,21,9,13,1,5,2…}. Thus the period is 8.
10. The appropriate value for m (in LCM) is
a) 2(31) – 1
b) 2(31)
c) 2(32)
d) 2(32) – 1
Explanation: Typically 2^(31) – 1 is chosen as the value for m (a large prime number).