Код програми яка створює ЕЦП.
 
# include <iostream.h>
#include <math.h>
//Зворотній елемент
int elem (int a,int b){
	int r[100];
	int m;
	r[0]=1;
	for(int i=0;i<100;i++)
		{if (b!=1){
		r[i]=b/a;
		int t=b%a;
		b=a;
		a=t;
		m=i;
		}
		else break;}
	int kol[3];
	kol[0]=r[0];
	kol[1]=r[0]*r[1]+1;
	if ((m-1)>1){
		for (int k=2; k<m; k++)
		{kol[k]=kol[k-1]*r[k]+kol[k-2];
		}
	}
	int y=pow(-1,m)*kol[m-1];
	return (y);
}
//ключі власний і відкритий 
void main (){
	int p=23;int n=7;int X1=13, Y1=7;int d=0;
	cout<<"Enter d from 1 to 7"<<endl;
	cin>>d;
	cout<<"Personal key="<<d<<endl;
	int X2,Y2;
		int yr=((3*X1*X1)+1);
		yr=yr%p;
		int l;
		int e=(2*Y1)%p;
		l=yr*elem(e,p);
		X2=(l*l-2*X1);
		X2=X2%p;
		Y2=(l*(X1-X2)-Y1);
		Y2=Y2%p;
		if (d>2){
			for (int i=1;i<d-1;i++)
			{
				int yr2=(Y1-Y2);
				yr2=yr2%p;
				int l2;
				int o=0;
				o=X1-X2;
				o=o%p;
				if (o<0) o=p+o;
				l2=yr2*elem(o,p);
				l2=l2%p;
				X2=(l2*l2-X1-X2);
				X2=X2%p;
				Y2=(l2*(X1-X2)-Y1);
				Y2=Y2%p;
			}
		}
if (X2<0) X2=p+X2;
if (Y2<0) Y2=p+Y2;
cout<<"The key is opened=("<<X2<<","<<Y2<<")"<<endl;
//ЕЦП
int w, ek, rk, sk;
cout<<"Enter the hesh value of report"<<endl;
cin>>ek;
ek=ek%n;
rk=X2;
rk=rk%n;
w=rk^ek;
int k=0;
	cout<<"Enter the session key from 1 to 7"<<endl;
	cin>>k;
	cout<<" value k="<<k<<endl;
	int X22,Y22;
		int yr1=((3*X1*X1)+1);
		yr1=yr1%p;
		if (yr1<0) yr1=p+yr1;
		int l1;
		int e1=(2*Y1)%p;
		l1=yr1*elem(e1,p);
		X22=(l1*l1-2*X1);
		X22=X22%p;
		if (X22<0) X22=p+X22;
		Y22=(l*(X1-X22)-Y1);
		Y22=Y22%p;
		if (Y22<0) Y22=p+Y22;
		if (k>2){
			for (int j=1;j<k-1;j++)
			{
				int yr22=(Y1-Y22);
				yr22=yr22%p;
				int l22;
				int o2=0;
				o2=X1-X22;
				o2=o2%p;
				if (o2<0) o2=p+o2;
				l22=yr22*elem(o2,p);
				l22=l22%p;
				if (X22<0) X22=p+X22;
				X22=(l22*l22-X1-X22);
				X22=X22%p;
				if (X22<0) X22=p+X22;
				Y22=(l22*(X1-X22)-Y1);
				Y22=Y22%p;
				if (Y22<0) Y22=p+Y22;
			}
		}
rk=X22;
rk=rk%n;
	cout<<"Digital signature EC-DSA"<<endl;
cout<<"r="<<rk<<endl;
w=elem(k,n);
sk=w*(ek+d*rk);
sk=sk%n;
if (sk<0) sk=n+sk;
cout<<"s="<<sk;
cin.get();
cin.get();
}