Question 6354 – Data-Structures
May 23, 2024UGC NET CS 2009-June-Paper-2
May 23, 2024UGC NET CS 2013 Dec-paper-2
| Question 5 |
Using the RSA public key cryptosystem, if p = 13, q = 31 and d = 7, then the value of ‘e’ is
| 101 | |
| 103 | |
| 105 | |
| 107 |
Question 5 Explanation:
Step-1: Compute n=p*q
= 13*31
= 403
Step-2: Compute f(n)= (p − 1)(q − 1)
= 12*30
= 360
Step-3: Compute d = e-1 mod f(n)
Choose an e such that 1
d.e = 1 mod f(n)
e = 1 mod 360
= 361 mod 360
= 721 mod 360
Note: Given d=7
7*e= 721 mod 360
e=103
= 13*31
= 403
Step-2: Compute f(n)= (p − 1)(q − 1)
= 12*30
= 360
Step-3: Compute d = e-1 mod f(n)
Choose an e such that 1
d.e = 1 mod f(n)
e = 1 mod 360
= 361 mod 360
= 721 mod 360
Note: Given d=7
7*e= 721 mod 360
e=103
Correct Answer: B
Question 5 Explanation:
Step-1: Compute n=p*q
= 13*31
= 403
Step-2: Compute f(n)= (p − 1)(q − 1)
= 12*30
= 360
Step-3: Compute d = e-1 mod f(n)
Choose an e such that 1
d.e = 1 mod f(n)
e = 1 mod 360
= 361 mod 360
= 721 mod 360
Note: Given d=7
7*e= 721 mod 360
e=103
= 13*31
= 403
Step-2: Compute f(n)= (p − 1)(q − 1)
= 12*30
= 360
Step-3: Compute d = e-1 mod f(n)
Choose an e such that 1
d.e = 1 mod f(n)
e = 1 mod 360
= 361 mod 360
= 721 mod 360
Note: Given d=7
7*e= 721 mod 360
e=103