#include "../lib/lib.h"
#include "../lib/lib2.h"
#include "../lib/lib3.h"
#include "../lib/lib4.h"
#include "../lib/lib5.h"
#include "../lib/lib6.h"
/**
  * you do not have the secrect key to sign the message
  * but you try to find a number which gives a "valid" padding
  * if the number is e-th rooted
  * to verfiy the signature the message is exponiated with e
  * when this didn't wrap around then it is a "valid" padding
  *
  * make the littlest possible number and exponiated it with e
  * hope that it did not wrap around and the e-th root is 
  *
  **/
int main()
{
	struct rsa_key_bignum public, private;
	SHA1Context sha1;

	BIGNUM *mess = BN_new();
	BIGNUM *forged = BN_new();
	BIGNUM *signed_mess = BN_new();
	BIGNUM *restored = BN_new();
	out = BIO_new(BIO_s_file());
	BIO_set_fp(out, stdout, BIO_NOCLOSE);

	ctx = BN_CTX_new();

	char *str_mess = "hi mom";
	char *sha1_hash[20];
	int pk_mess_len = 20 + strlen(str_mess) + 4 + 50;
	char *pk_mes = malloc(pk_mess_len);
	
	rsa_generate_key_bignum(&public, &private);

	SHA1Reset(&sha1);
	SHA1Input(&sha1, str_mess, strlen(str_mess));
	SHA1Result(&sha1);
	memcpy(sha1_hash, &(sha1.Message_Digest), 20);

	pk_mes[0] = 0x00;
	pk_mes[1] = 0x01;
	pk_mes[2] = 0xff;
	pk_mes[3] = 0x00;
	memcpy(&pk_mes[4], sha1_hash, 20);

	// does this padding verify?
	printf("padding verfied: %i\n", shitty_pkcs1_5_padding_verify(pk_mes, pk_mess_len, str_mess));
	BN_bin2bn(pk_mes, pk_mess_len, mess);
	// sign with knowing the private key
	//rsa_encrypt_bignum(mess, signed_mess, &private);
	// "sign" without knowing the private key
	BIGNUM *n3 = BN_new();
	BN_set_word(n3, 3);
	nth_root_bignum(signed_mess, mess, n3);


	// verfiy
	rsa_decrypt_bignum(signed_mess, restored, &public);

	char *rest_mess = malloc(BN_num_bytes(restored));
	BN_bn2bin(restored, rest_mess);

	printf("\nverfied after cube root and exp: %i\n", shitty_pkcs1_5_padding_verify(rest_mess, BN_num_bytes(restored), str_mess));
	printf("padding from better verifier function: %i\n",
		pkcs1_5_padding_verify(pk_mes, pk_mess_len, str_mess));
}