crypt.m
function mc = crypt(M,N,e)
e=dec2bin(e);
k = 65535;
c = M;
cf = 1;
cf=mod(c*cf,N);
for i=k-1:-1:1
c = mod(c*c,N);
j=k-i+1;
if e(j)==1
cf=mod(c*cf,N);
end
end
mc=cf;
dec2bin.m
function a = dec2bin(d)
i=1;
a=zeros(1,65535);
while d >= 2
r=rem(d,2);
if r==1
a(i)=1;
else
a(i)=0;
end
i=i+1;
d=floor(d/2);
end
if d == 2
a(i) = 0;
else
a(i) = 1;
end
x=[a(16) a(15) a(14) a(13) a(12) a(11) a(10) a(9) a(8) a(7) a(6) a(5)
initialize.m
function [Pk,Phi,d,e] = intialize(p,q)
clc;
disp('Intaializing:');
Pk=p*q;
Phi=(p-1)*(q-1);
%Calculate the value of e
x=2;e=1;
while x > 1
e=e+1;
x=gcd(Phi,e);
end
%Calculate the value of d
i=1;
r=1;
while r > 0
k=(Phi*i)+1;
r=rem(k,e);
i=i+1;
end
d=k/e;
clc;
disp(['The value of (N) is: ' num2str(Pk)]);
disp(['The public key (e) is: ' num2str(e)]);
disp(['The value of (Phi) is: ' num2str(Phi)]);
disp(['The private key (d)is: ' num2str(d)]);
rsa.m
clc;
disp('Implementation of RSA Algorithm');
clear all; close all;
p = input('\nEnter the value of p: ');
q = input('\nEnter the value of q: ');
[Pk,Phi,d,e] = intialize(p,q);
M = input('\nEnter the message: ','s');
x=length(M);
c=0;
for j= 1:x
for i=0:122
if strcmp(M(j),char(i))
c(j)=i;
end
end
end
disp('ASCII Code of the entered Message:');
disp(c);
% % %Encryption
for j= 1:x
cipher(j)= crypt(c(j),Pk,e);
end
disp('Cipher Text of the entered Message:');
disp(cipher);
% % %Decryption
for j= 1:x
message(j)= crypt(cipher(j),Pk,d);
end
disp('Decrypted ASCII of Message:');
disp(message);
disp(['Decrypted Message is: ' message]);
