#include "../lib/lib.h"
#include "../lib/lib2.h"
#include "../lib/lib3.h"
#include "../lib/lib4.h"
#include "../lib/lib5.h"
#include <time.h>


int DH_smallnums()
{
	srand(time(NULL));
	// public prime numbers; everbody can know them, parameters of the
	// expoential function
	unsigned int p = 37;
	unsigned int g = 5;
	// exponents of the dicrect exponential function, should be kept secret
	unsigned int b;
	unsigned int a;
	generate_random_bytes((char *)&a,4);
	a = a % p;
	generate_random_bytes((char *)&b,4);
	b = b % p;
	// A and B are the public keys, sent to each other
	// one cannot infer a/b from A/B
	unsigned A = g ^ a % p;
	unsigned B = g ^ b % p;
	// both compute these number, s1 = s2; (g^a)^b = (g^b)^a
	unsigned int s1 = B ^ a % p;
	unsigned int s2 = A ^ b % p;

	printf("session key A: %i\n", s1);
	printf("session key B: %i\n", s2);

	// generate a key, 128 bit by hashing the session key
}

void DH_bignums()
{
	struct dh_param_bignum dh;

	do_dh_key_exchange_bignum(&dh);

	printf("bignums: A: ");
	BN_print(out, dh.A);
	printf("\nbignums: session key 1: ");
	BN_print(out, dh.s1);
	printf("\nbignums: session key 2: ");
	BN_print(out, dh.s2);

	if(BN_cmp(dh.s1, dh.s2) == 0)
		printf("\nboth session keys are equal!\n");
}

int main()
{
	out = BIO_new(BIO_s_file());
	BIO_set_fp(out, stdout, BIO_NOCLOSE);

	ctx = BN_CTX_new();
	DH_smallnums();
	DH_bignums();
}