Description : Using the RSA public key crypto system, if p=13, q=31 and d=7, then the value of e is (A) 101 (B) 105 (C) 103 (D) 107
Last Answer : (C) 103 Explanation: Basic RSA Algorithm: 1. Choose two primes, p & q. 2. Compute n=p*q and z=(p-1)*(q-1). 3. Choose a number relatively prime to z and call it d. 4. Find e such that e*d= ... each of these in turn by 7 to see which is divisible by 7, we find that 721/7 = 103, hence e = 103.