//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

extern "C" 
{ 
#include "miracl.h"
}
//#include <stdio.h>
//#include <windows.h>
#include <math.h>

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"

TForm1 *Form1;
miracl *mip=mirsys(5000,10);
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------
void GenPrimes(big a, big b, int BITS)
{
   csprng RNG;
   strong_init(&RNG,1,"a",GetTickCount());
   //Generate Prime 1
   strong_bigdig(&RNG,BITS,10,a);
   if(subdivisible(a,2))
   {
      incr(a,1,a);
   }
   while(!isprime(a))
   {
      incr(a,2,a);
      //cotnum(a,stdout);
   }
   //Generate Prime 2
   strong_bigdig(&RNG,BITS,10,b);
   if(subdivisible(b,2))
   {
      incr(b,1,b);
   }
   while(!isprime(b))
   {
      incr(b,2,b);
   }
}

//Generates F which is (P-1)(Q-1)
void GenF(big p, big q, big f)
{
   big p1=mirvar(0),q1=mirvar(0);
   decr(p,1,p1);
   decr(q,1,q1);
   multiply(p1,q1,f);
}

//Generates number E for RSA encryption.
//Number is BITS long and requires an F 
void GenE(big f, big e, int BITS)
{
   csprng RNG;
   big x=mirvar(0);
   big z=mirvar(0);

   convert(1,x);
   strong_init(&RNG,1,"a",GetTickCount());
   strong_bigdig(&RNG,BITS/2,10,e);
   //cotnum(e,stdout);
   if(subdivisible(e,2))
   {
      //cotnum(e,stdout);
      incr(e,1,e);
   }
   //cotnum(z,stdout);
   egcd(f,e,z);
   while(compare(z,x)!=0)
   {
      incr(e,2,e);
      egcd(f,e,z);
      //cotnum(e,stdout);
   }
}

//Generates D. don't quite know how. Requires a variable to store it
//D and requres E and number F
void GenD(big d,big e, big f)
{
   copy(e,d);
   xgcd(d,f,d,d,d);
}
void RSAEnc(big plaintext, big e, big p, big q, big cyphered)
{
   big pq = mirvar(0);
   multiply(p,q,pq);
   powmod(plaintext,e,pq,cyphered);
}
void RSADec(big t, big e, big p, big q, big w)
{
   big pq = mirvar(0);
   multiply(p,q,pq);
   powmod(t,e,pq,w);
}


void __fastcall TForm1::Button1Click(TObject *Sender)
{
   int BITS=2048;
   BITS=ceil((BITS)*log10(2.0)/2);
   //2048/log[2](10) = number of digits in a 2048 bit number.
   char *nump;
   char *numq;
	big p,q,f,p1,q1,e,d,n,w,l;
   char *nick;
   String A;
   nick = (char*)malloc(258);
   p=mirvar(0);
   q=mirvar(0);
   f=mirvar(0);
   e=mirvar(0);
   d=mirvar(0);
   n=mirvar(0);
   w=mirvar(0);
   l=mirvar(0);
   convert(695,n);
   
   nump = new char[256+1];
   numq = new char[256+1];
   GenPrimes(p,q,BITS);
   big_to_bytes(257,p,nump,false);
   big_to_bytes(257,q,numq,false);
   cotstr(p,nick);
   A=nick;
   Form1->Memo1->Text = A;
   cotstr(q,nick);
   A=nick;
   Form1->Memo2->Text = A;
   //printf("P=");

   //cotnum(p,stdout);
   //printf("Q=");
   //cotnum(q,stdout);

   GenF(p,q,f);
   cotstr(f,nick);
   A=nick;
   Form1->Memo3->Text = A;

   GenE(f,e,BITS);
   cotstr(e,nick);
   A=nick;
   Form1->Memo4->Text = A;

   GenD(d,e,f);
   cotstr(d,nick);
   A=nick;
   Form1->Memo5->Text = A;

   RSAEnc(n,e,p,q,w);
   //printf("Cipher=");
   //cotnum(w,stdout);

   RSADec(w,d,p,q,l);
   //printf("Plaintext=");
   //cotnum(l,stdout);
}
//---------------------------------------------------------------------------