Playfair Cipher 1.not even the large number of keys in a monoalphabetic cipher provides security 2.one approach to improving security was to encrypt multiple letters 3.the Playfair Cipher is an example 4.invented by Charles Wheatstone in 1854

Fermats test to check for primality. Code is in java. takes a e=random number and gives whether it is prime or not.

This a new algorithm in which we encrypt on the basis of position of the character. Algorithm 1 for key generation and Algorithm 2 is for encryption Algorithm A1 Step1: Let the key be ‘k’. Step2: Multiply the index number +1 with its ASCII c