使用LibTomCrypt实现RSA加密解密算法，公钥、私钥分离-蒲公英云

//使用本代码需要先下载LibTomMath和LibTomCrypt库
//编译LibTomMath、LibTomCrypt后生成lib文件
//在本工程的包含目录中添加LibTomCrypt的头文件目录
//链接器中添加LibTomCrypt、LibTomMath的Lib文件
#include <Windows.h>
#include <stdio.h>
#define LTM_DESC
#include <tomcrypt.h>
#include <time.h>
#define PTSIZE 87
#define CPSIZE 1024
#define BUFFERSIZE 1024
//按照16进制方式打印字符串
void strprint(const char * name,unsigned char *msg,int len);
//对比两个字符数组如果完全匹配返回0，否则返回负数
int msgcmp(unsigned char *msg1,unsigned long l1,unsigned char *msg2,unsigned long l2);
int main(void)
{    
    char c;
    int prng_idx,hash_idx,err;
    unsigned char pt[PTSIZE],pt1[CPSIZE],cp[CPSIZE];
    unsigned char out[BUFFERSIZE];
    unsigned long l1,l2;
    rsa_key key;
    rsa_key pubkey,prikey;
    unsigned char pubkeybuffer[BUFFERSIZE], prikeybuffer[BUFFERSIZE];
    unsigned long pubkeybuffersize, prikeybuffersize;
    int keysize = 0;
    int stat;
    int n;
    LARGE_INTEGER t1, t2, tc;
    QueryPerformanceFrequency(&tc);
    /*********解析算法准备**********/
    //绑定数学库
    ltc_mp = ltm_desc;
    //注册随机数生成器
    register_prng(&sprng_desc);
    prng_idx = find_prng("sprng");
    //注册hash运算库
    register_hash(&sha1_desc);
    hash_idx = find_hash("sha1");    
    /*********生成key**********/
    //生成一个新的key
    err = rsa_make_key(NULL, prng_idx, 1024 / 8, 257, &key);
    if (err != CRYPT_OK)
    {
        printf("rsa_make_key err:%s\n",error_to_string(err));
        goto MAIN_FUNC_RET;
    }
    //打印Key的长度
    keysize = rsa_get_size(&key);
    if (keysize < 0)
    {
        printf("rsa_get_size err:%s\n", error_to_string(err));
        goto MAIN_FUNC_RET;
    }
    printf("keysize = %d\n",keysize);
    //将key导出成为私密秘钥形势的字符串，做单独保存
    err = rsa_export(prikeybuffer, &prikeybuffersize, PK_PRIVATE, &key);
    if (err != CRYPT_OK)
    {
        printf("rsa_export err:%s\n", error_to_string(err));
        goto MAIN_FUNC_RET;
    }
    strprint("prikey", prikeybuffer, prikeybuffersize);
    //将key导出成为公共秘钥形势的字符串，公开加密使用
    err = rsa_export(pubkeybuffer, &pubkeybuffersize, PK_PUBLIC, &key);
    if (err != CRYPT_OK)
    {
        printf("rsa_export err:%s\n", error_to_string(err));
        goto MAIN_FUNC_RET;
    }
    strprint("pubkey", pubkeybuffer, pubkeybuffersize);
    //从公共秘钥字符串中导入成rsa_key加密使用
    err = rsa_import(pubkeybuffer, pubkeybuffersize, &pubkey);
    if (err != CRYPT_OK)
    {
        printf("rsa_import err:%s\n", error_to_string(err));
        goto MAIN_FUNC_RET;
    }
    n = rsa_get_size(&pubkey);
    printf("pubkeysize = %d\n",n);
    //从私密秘钥字符串中导入成为rsa_key解密使用
    err = rsa_import(prikeybuffer, prikeybuffersize, &prikey);
    if (err != CRYPT_OK)
    {
        printf("rsa_import err:%s\n", error_to_string(err));
        goto MAIN_FUNC_RET;
    }
    n = rsa_get_size(&prikey);
    if (n < 0)
    {
        printf("rsa_get_size err:%s\n", error_to_string(err));
        goto MAIN_FUNC_RET;
    }
    printf("prikeysize = %d\n",n);
    system("pause");
    /*****************加密和解密验证******************/
    memset(pt, 0, PTSIZE);
    srand(time(0));
    //随机生成一个字符数组作为待加密原文
    for (int i = 0; i < PTSIZE; i++)
    {
        pt[i] = rand() % 255;
    }
    strprint("pt", pt, PTSIZE);
    //多次尝试加密解密，验证结果，计算运算时间
    for (int i = 0; i < 100; i++)
    {
        memset(cp,0,CPSIZE);
        QueryPerformanceCounter(&t1);
        rsa_encrypt_key_ex(pt, PTSIZE, cp, &l1, (const unsigned char*)"abcde", 5, NULL, prng_idx, hash_idx, LTC_PKCS_1_V1_5, &pubkey);
        QueryPerformanceCounter(&t2);
        strprint("encrypt text",cp,l1);
        printf("加密运算时间:%f\n", (t2.QuadPart - t1.QuadPart)*1000.0 / tc.QuadPart);
        //尝试使用公开秘钥进行解密失败
        QueryPerformanceCounter(&t1);
        //rsa_decrypt_key_ex(cp, l1, pt1, &l2, (const unsigned char*)"abcde", 5, hash_idx, LTC_PKCS_1_V1_5,&stat, &pubkey);
        rsa_decrypt_key_ex(cp, l1, pt1, &l2, (const unsigned char*)"abcde", 5, hash_idx, LTC_PKCS_1_V1_5, &stat, &prikey);
        QueryPerformanceCounter(&t2);
        printf("stat = %d\n",stat);
        strprint("decrypt text",pt,l2);
        printf("解密运算时间:%f\n", (t2.QuadPart - t1.QuadPart)*1.0 / tc.QuadPart);
        printf("解密后对比结果：%s\n",msgcmp(pt,PTSIZE,pt1,l2) == 0 ? "正确" : "错误");
        system("pause");
    }
MAIN_FUNC_RET:
    rsa_free(&key);
    rsa_free(&prikey);
    rsa_free(&pubkey);
    system("pause");
    return 0;
}
void strprint(const char * name, unsigned char *msg, int len)
{
    printf("name = %s,len = %d\n", name, len);
    for (int i = 0; i < len; i++)
    {
        if (i != 0 && i % 32 == 0)
        {
            printf("\n");
        }
        printf("0x%02x,", msg[i]);
    }
    printf("\n");
}
int msgcmp(unsigned char *msg1, unsigned long l1, unsigned char *msg2, unsigned long l2)
{
    if (l1 != l2)
        return -1;
    for (int i = 0; i < l1; i++)
    {
        if (msg1[i] != msg2[i])
        {
            return -2;
        }
    }
    return 0;
}