59 lines
1.1 KiB
C++
59 lines
1.1 KiB
C++
/*
|
|
* Test program to implement the Comb method for fast
|
|
* computation of e.G on the elliptic curve E(F_p) for fixed G and E,
|
|
* using precomputation.
|
|
* This idea can be used to substantially speed up certain phases
|
|
* of the Elliptic Curve Digital Signature Standard (DSS).
|
|
*
|
|
* See "Handbook of Applied Cryptography", CRC Press, 2001
|
|
*
|
|
* Requires: big.cpp ecn.cpp
|
|
*
|
|
*/
|
|
|
|
#include <iostream>
|
|
#include <fstream>
|
|
#include "ecn.h"
|
|
#include "ebrick.h" /* include MIRACL system */
|
|
|
|
using namespace std;
|
|
|
|
Miracl precision=50;
|
|
|
|
int main()
|
|
{
|
|
ifstream common("common.ecs");
|
|
Big a,b,x,y,e,n,r;
|
|
int bits,nb,w;
|
|
miracl *mip=&precision;
|
|
common >> bits;
|
|
mip->IOBASE=16;
|
|
common >> n >> a >> b >> r >> x >> y;
|
|
mip->IOBASE=10;
|
|
|
|
w=8; // window size
|
|
|
|
cout << "Enter size of exponent in bits = ";
|
|
cin >> nb;
|
|
|
|
EBrick B(x,y,a,b,n,w,nb);
|
|
|
|
e=rand(nb,2); /* random exponent */
|
|
|
|
cout << "naive method" << endl;
|
|
ecurve(a,b,n,MR_PROJECTIVE);
|
|
ECn G(x,y);
|
|
G*=e;
|
|
G.get(x,y);
|
|
cout << x << endl;
|
|
|
|
x=0;
|
|
cout << "Comb method" << endl;
|
|
|
|
B.mul(e,x,y);
|
|
|
|
cout << x << endl;
|
|
return 0;
|
|
}
|
|
|