main.c

用VC实现的一个RSA加密算法

#include "bn.h"
#include <conio.h>
#include <stdio.h>

#define RSA_N_SIZE 1024
#define RSA_P_SIZE (((RSA_N_SIZE) + 1) >> 1)
#define RSA_Q_SIZE ((RSA_N_SIZE) - (RSA_P_SIZE))
#define RSA_EN_SIZE RSA_N_SIZE
#define RSA_D_SIZE RSA_EN_SIZE
#define BYTENUM(a) (((a) & 7)? (((a) >> 3) + 1): ((a) >> 3))

typedef int S32;
typedef unsigned int U32;
typedef unsigned char U8;

int
random_number(unsigned char *dst, int len, void *dat);

S32
main(void)
{
	S32 err, i, t;
	U8 p[BYTENUM(RSA_P_SIZE)];
	U8 q[BYTENUM(RSA_Q_SIZE)];
	U8 n[BYTENUM(RSA_N_SIZE)];
	U8 e[3]={1, 0, 1};
	U8 d[BYTENUM(RSA_D_SIZE)];
	U8 en[BYTENUM(RSA_EN_SIZE)];

	mp_int _p, _q, _n, _e, _d, _en;
    if((err = mp_init_multi(&_p, &_q, &_n, &_e, &_d, &_en, NULL)) != MP_OKAY)
	{
		goto LIF;
	}
	//获得素数P的审判次数
    t=mp_prime_rabin_miller_trials(RSA_P_SIZE);
	//生成大素数P

    if((err = mp_prime_random_ex(&_p, t, RSA_P_SIZE, LTM_PRIME_2MSB_ON, random_number, NULL)) != MP_OKAY)
	{
		goto LBL;
	}

	dump_mp_int_to_char (&_p, BYTENUM(RSA_P_SIZE), (char *)p);

	printf("p:\n");
	for (i = 0; i < BYTENUM(RSA_P_SIZE); ++i)
	{
		printf("0x%02X, ", p[i]);
		if (7 == (i & 7))
		{
			printf("\n");
		}
	}   
	
	//获得素数Q的审判次数
	t=mp_prime_rabin_miller_trials(RSA_Q_SIZE);
	//生成大素数P

    if((err = mp_prime_random_ex(&_q, t, RSA_Q_SIZE, LTM_PRIME_2MSB_ON, random_number, NULL)) != MP_OKAY)
	{
		goto LBL;
	}

	dump_mp_int_to_char (&_q, BYTENUM(RSA_P_SIZE), (char *)q);

	printf("\nq:\n");
	for (i = 0; i < BYTENUM(RSA_P_SIZE); ++i)
	{
		printf("0x%02X, ", q[i]);
		if (7 == (i & 7))
		{
			printf("\n");
		}
	}   


	//计算n=p*q
    if ((err = mp_mul(&_p, &_q, &_n)) != MP_OKAY) 
	{
		goto LBL;
	}
	dump_mp_int_to_char (&_n, BYTENUM(RSA_N_SIZE), (char *)n);

	printf("\nn:\n");
	for (i = 0; i < BYTENUM(RSA_N_SIZE); ++i)
	{
		printf("0x%02X, ", n[i]);
		if (7 == (i & 7))
		{
			printf("\n");
		}
	}   
	//计算p-1
    if ((err = mp_sub_d (&_p, 1, &_p)) != MP_OKAY) 
	{
		goto LBL;
	}
	//计算q-1
    if ((err = mp_sub_d (&_q, 1, &_q)) != MP_OKAY) 
	{
		goto LBL;
	}
	//计算(p-1)*(q-1)
    if ((err = mp_mul (&_p, &_q, &_en)) != MP_OKAY) 
	{
		goto LBL;
	}
	dump_mp_int_to_char (&_en, BYTENUM(RSA_EN_SIZE), (char *)en);
	printf("\nen:\n");
	for (i = 0; i < BYTENUM(RSA_EN_SIZE); ++i)
	{
		printf("0x%02X, ", en[i]);
		if (7 == (i & 7))
		{
			printf("\n");
		}
	}
	   
    if ((err = mp_read_unsigned_bin(&_e, e, 3)) != MP_OKAY) 
	{
		goto LBL;
	}
	//计算d=e^-1 mod (p-1)*(q-1)
    if ((err = mp_invmod(&_e, &_en, &_d)) != MP_OKAY) 
	{
		goto LBL;
	}
	dump_mp_int_to_char (&_d, BYTENUM(RSA_D_SIZE), (char *)d);
	printf("\nd:\n");
	for (i = 0; i < BYTENUM(RSA_D_SIZE); ++i)
	{
		printf("0x%02X, ", d[i]);
		if (7 == (i & 7))
		{
			printf("\n");
		}
	}

LBL:mp_clear_multi(&_p, &_q, &_n, &_e, &_d, &_en, NULL);
LIF:
	printf("Press any key to continue");
	getch();
	return err;
}