Diff: rsa-small-numbers.cpp

Revision:

0:65a36a7b25d0

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rsa-small-numbers.cpp	Sat Nov 10 20:11:01 2018 +0000
@@ -0,0 +1,48 @@
+#include<iostream>
+#include<math.h>
+
+int gcd(int a, int h)
+{
+    int temp;
+    while (1)
+    {
+        temp = a%h;
+        if (temp == 0)
+          return h;
+        a = h;
+        h = temp;
+    }
+}
+
+int main()
+{
+    double p = 3;
+    double q = 7;
+    double n = p*q;
+    double e = 2;
+    double phi = (p-1)*(q-1);
+    while (e < phi)
+    {
+       
+        if (gcd(e, phi)==1)
+            break;
+        else
+            e++;
+    }
+
+    int k = 2; 
+    double d = (1 + (k*phi))/e;
+
+    double msg = 20;
+
+    printf("Message data = %lf", msg);
+    double c = pow(msg, e);
+    c = fmod(c, n);
+    printf("\nEncrypted data = %lf", c);
+
+    double m = pow(c, d);
+    m = fmod(m, n);
+    printf("\nOriginal Message Sent = %lf", m);
+
+    return 0;
+}