RSA Algorithm Implementation
#include<iostream>
#include<math.h>
using namespace std;
// find gcd
int gcd(int a, int b) {
int t;
while(1) {
t= a%b;
if(t==0)
return b;
a = b;
b= t;
}
}
int main() {
double p = 13;
double q = 11;
double n=p*q;
double track;
double phi= (p-1)*(q-1);
double e=7;
while(e<phi) {
track = gcd(e,phi);
if(track==1)
break;
else
e++;
}
double d1=1/e;
double d=fmod(d1,phi);
double message = 9;
double c = pow(message,e);
double m = pow(c,d);
c=fmod(c,n);
m=fmod(m,n);
cout<<"Original Message = "<<message;
cout<<"\n"<<"p = "<<p;
cout<<"\n"<<"q = "<<q;
cout<<"\n"<<"n = pq = "<<n;
cout<<"\n"<<"phi = "<<phi;
cout<<"\n"<<"e = "<<e;
cout<<"\n"<<"d = "<<d;
cout<<"\n"<<"Encrypted message = "<<c;
cout<<"\n"<<"Decrypted message = "<<m;
return 0;
}
output:
Original Message = 9
p = 13
q = 11
n = pq = 143
phi = 120
e = 7
d = 0.142857
Encrypted message = 48
Decrypted message = 9
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