#include "../lib/lib.h"
#include "../lib/lib2.h"
#include "../lib/lib3.h"
#include "../lib/lib4.h"
#include "../lib/lib5.h"
#include "../lib/lib6.h"
#include <openssl/sha.h>

int main()
{
	int i;
	struct dsa_public_params dsa_pub;
	struct dsa_per_user_param dsa_user;
	struct dsa_per_user_param dsa_user_org;
	BIGNUM *hash_bn = BN_new();
	BIGNUM *k = BN_new();
	char *message = "For those that envy a MC it can be hazardous to your health\nSo be friendly, a matter of life and death, just like a etch-a-sketch\n";
	
	out = BIO_new(BIO_s_file());
	BIO_set_fp(out, stdout, BIO_NOCLOSE);
	ctx = BN_CTX_new();

	printf("message is:\n%s\n", message);
	SHA_CTX sha1;
	char sha1_hash[20];
	char hex[40];
	dsa_user.public = BN_new();
	dsa_user.private = BN_new();
	dsa_user.r= BN_new();
	dsa_user.s = BN_new();

	dsa_user_org.public = BN_new();
	dsa_user_org.private = BN_new();
	dsa_user_org.r= BN_new();
	dsa_user_org.s = BN_new();

	SHA1_Init(&sha1);
	SHA1_Update(&sha1, message, strlen(message));
	SHA1_Final(sha1_hash, &sha1);
	hex_binary_to_string(sha1_hash, hex, 20);
	printf("hash of message is: %s\n", hex);
	BN_bin2bn(sha1_hash, 20, hash_bn);
	BN_print(out, hash_bn);

	init_dsa_pub_param(&dsa_pub);

	// set public key
	char *  y = "84ad4719d044495496a3201c8ff484feb45b962e7302e56a392aee4"
	"abab3e4bdebf2955b4736012f21a08084056b19bcd7fee56048e004"
	"e44984e2f411788efdc837a0d2e5abb7b555039fd243ac01f0fb2ed"
	"1dec568280ce678e931868d23eb095fde9d3779191b8c0299d6e07b"
	"bb283e6633451e535c45513b2d33c99ea17";
	char *r = "548099063082341131477253921760299949438196259240";
	char *s = "857042759984254168557880549501802188789837994940";

	BN_hex2bn(&dsa_user.public, y);
	// well this is decimal ....
	BN_dec2bn(&dsa_user.r, r);
	BN_dec2bn(&dsa_user.s, s);

	BN_copy(dsa_user_org.public, dsa_user.public);
	BN_copy(dsa_user_org.r, dsa_user.r);
	BN_copy(dsa_user_org.s, dsa_user.s);

	// can i verfiy that?
	// brute force
	BIGNUM *tmp = BN_new();
	for(i=0;i<65536;i++) {
		BN_set_word(k, i);
		//BN_copy(dsa_user.r, dsa_user_org.r);
		//BN_copy(dsa_user.s, dsa_user_org.s);
		//BN_copy(dsa_user.public, dsa_user_org.public);
		dsa_recover_x_from_known_k(&dsa_pub, k, &dsa_user, hash_bn);
		// compute signture with this x,k and compare
		printf("\nprivate key for k = %i\n", i);
		BN_print(out, dsa_user.private);
		//dsa_sign(message, &dsa_pub, &dsa_user, k);	
		BN_mod_exp(tmp, dsa_pub.g, dsa_user.private, dsa_pub.p, ctx);
		if(!BN_cmp(tmp, dsa_user.public))
			break;
	}
	printf("\nk is: %i, private key:\n", i);
	BN_print(out, dsa_user.private);
	char *str_priv = malloc(BN_num_bytes(dsa_user.private));
	char *str_priv_hex = malloc(BN_num_bytes(dsa_user.private)*2+1);
	BN_bn2bin(dsa_user.private, str_priv);
	hex_binary_to_string(str_priv, str_priv_hex, BN_num_bytes(dsa_user.private));

	SHA1_Init(&sha1);
	SHA1_Update(&sha1, str_priv_hex, BN_num_bytes(dsa_user.private)*2);
	SHA1_Final(sha1_hash, &sha1);

	char *given_hash = "0954edd5e0afe5542a4adf012611a91912a3ec16";
	hex_binary_to_string(sha1_hash, hex, 20);
	printf("\nhash of private key is: %s\n", hex);
	printf("given one: %s\n", given_hash);
	printf("equal?: %i", !memcmp(hex, given_hash, 20));
}