使用LibTomCrypt实现RSA加密解密算法，公钥、私钥分离

水深无声 2022-03-08 16:50 459阅读 0赞

//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;
    }

[https://download.csdn.net/download/haozi596/10308358][https_download.csdn.net_download_haozi596_10308358]

[https_download.csdn.net_download_haozi596_10308358]: https://download.csdn.net/download/haozi596/10308358