UGC-NET Computer Science (RSA-Algorithm Solution)

UGC-NET RSA-Algorithm Solution

Using RSA algorithm, what is the value of cipher text C, if the plain text M = 5 and p = 3, q = 11 & d = 7 ? 

(A) 20

(B) 52 

(C ) 26 

(D )31

Solution:-

All the values are given i.e.

p=3,

q=11

      then n=(p * q) = (3 * 11)=33

   Find value of m=(p-1)*(q-1) = (2 * 10)=20

Find a small odd integer e, that is relatively prime to m.

If e=3, then GCD(3,20)=1. e should be small and prime and so we let e=3. Value of d is given, d=7.

Public key = (e,n).

To encrypt a message, we apply the public key to the function 

E(m) = m^e(mod n)

then:-

   =5³(mod 33)

   = 125 (mod 33)

   = 26

As a result, the encrypted message E(M) = 26.

It is the transmitting message.