UGC NET CSE | December 2015 | Part 2 | Question: 25

Question

Using p=3, q=13, d=7 and e=3 in the RSA algorithm, what is the value of ciphertext for a plain text 5?

• A. 13
• B. 21
• C. 26
• D. 33

Answer 1

all options are incorrect and perhaps question too

everything (e,d,p,q,P) is given in question just need to verfiy from the ans but options are not verificable

C=P^e mod n

P=5 , e=3 ,n=pq=39

C=5^3mod39=>125mod39=8 not in option

Answer 2

Encryption: C=T^e (mod pq) =5^3(mod39) =26mod39 =26

Comments

How 5*3 gives you 26?..

its 125mod39 so ans is 8 .no option is correct