1. openssl庫文件及頭文件的獲取
獲取openssl庫文件及頭文件有兩種方式:
1)下載OpenSSL源代碼並由自己編譯後使用
2)下載已編譯好的安裝包,安裝後直接可以得到openssl的庫文件及頭文件
使用第一種方法獲取,過程十分繁瑣,同時編譯過程中可能產生各種各種的問題,因此這裏使用第二種方法獲取openssl庫文件及頭文件。
下載安裝包(https://slproweb.com/products/Win32OpenSSL.html),並進行安裝,安裝後安裝目錄如下圖,其中bin文件夾內的爲動態庫文件、lib文件夾內的爲靜態庫文件、include文件夾內的爲頭文件
2. 使用openssl對數據進行加解密
1) 新建工程,引入openssl頭文件及庫文件
2) 示例代碼如下,示例代碼包含了:
a. 摘要(散列)算法md5、sha256;
b. 對稱加密算法des;
c. 非對稱加密算法rsa。
#include <iostream>
#include <cassert>
#include <string>
#include <vector>
#include "openssl/md5.h"
#include "openssl/sha.h"
#include "openssl/des.h"
#include "openssl/rsa.h"
#include "openssl/pem.h"
#pragma comment(lib,"libcrypto.lib")
// ---- md5摘要哈希 ---- //
void md5(const std::string &srcStr, std::string &encodedStr, std::string &encodedHexStr)
{
unsigned char mdStr[33] = { 0 };
MD5((const unsigned char *)srcStr.c_str(), srcStr.length(), mdStr);// 調用md5哈希
encodedStr = std::string((const char *)mdStr);// 哈希後的字符串
char buf[65] = { 0 };
char tmp[3] = { 0 };
for (int i = 0; i < 32; i++)// 哈希後的十六進制串 32字節
{
sprintf(tmp, "%02x", mdStr[i]);
strcat(buf, tmp);
}
buf[32] = '\0'; // 後面都是0,從32字節截斷
encodedHexStr = std::string(buf);
}
// ---- sha256摘要哈希 ---- //
void sha256(const std::string &srcStr, std::string &encodedStr, std::string &encodedHexStr)
{
unsigned char mdStr[33] = { 0 };
SHA256((const unsigned char *)srcStr.c_str(), srcStr.length(), mdStr);// 調用sha256哈希
encodedStr = std::string((const char *)mdStr);// 哈希後的字符串
char buf[65] = { 0 };
char tmp[3] = { 0 };
for (int i = 0; i < 32; i++)// 哈希後的十六進制串 32字節
{
sprintf(tmp, "%02x", mdStr[i]);
strcat(buf, tmp);
}
buf[32] = '\0'; // 後面都是0,從32字節截斷
encodedHexStr = std::string(buf);
}
// ---- des對稱加解密 ---- //
// 加密 ecb模式
std::string des_encrypt(const std::string &clearText, const std::string &key)
{
std::string cipherText; // 密文
DES_cblock keyEncrypt;
memset(keyEncrypt, 0, 8);
// 構造補齊後的密鑰
if (key.length() <= 8)
memcpy(keyEncrypt, key.c_str(), key.length());
else
memcpy(keyEncrypt, key.c_str(), 8);
// 密鑰置換
DES_key_schedule keySchedule;
DES_set_key_unchecked(&keyEncrypt, &keySchedule);
// 循環加密,每8字節一次
const_DES_cblock inputText;
DES_cblock outputText;
std::vector<unsigned char> vecCiphertext;
unsigned char tmp[8];
for (int i = 0; i < clearText.length() / 8; i++)
{
memcpy(inputText, clearText.c_str() + i * 8, 8);
DES_ecb_encrypt(&inputText, &outputText, &keySchedule, DES_ENCRYPT);
memcpy(tmp, outputText, 8);
for (int j = 0; j < 8; j++)
vecCiphertext.push_back(tmp[j]);
}
if (clearText.length() % 8 != 0)
{
int tmp1 = clearText.length() / 8 * 8;
int tmp2 = clearText.length() - tmp1;
memset(inputText, 0, 8);
memcpy(inputText, clearText.c_str() + tmp1, tmp2);
DES_ecb_encrypt(&inputText, &outputText, &keySchedule, DES_ENCRYPT);// 加密函數
memcpy(tmp, outputText, 8);
for (int j = 0; j < 8; j++)
vecCiphertext.push_back(tmp[j]);
}
cipherText.clear();
cipherText.assign(vecCiphertext.begin(), vecCiphertext.end());
return cipherText;
}
// 解密 ecb模式
std::string des_decrypt(const std::string &cipherText, const std::string &key)
{
std::string clearText; // 明文
DES_cblock keyEncrypt;
memset(keyEncrypt, 0, 8);
if (key.length() <= 8)
memcpy(keyEncrypt, key.c_str(), key.length());
else
memcpy(keyEncrypt, key.c_str(), 8);
DES_key_schedule keySchedule;
DES_set_key_unchecked(&keyEncrypt, &keySchedule);
const_DES_cblock inputText;
DES_cblock outputText;
std::vector<unsigned char> vecCleartext;
unsigned char tmp[8];
for (int i = 0; i < cipherText.length() / 8; i++)
{
memcpy(inputText, cipherText.c_str() + i * 8, 8);
DES_ecb_encrypt(&inputText, &outputText, &keySchedule, DES_DECRYPT);
memcpy(tmp, outputText, 8);
for (int j = 0; j < 8; j++)
vecCleartext.push_back(tmp[j]);
}
if (cipherText.length() % 8 != 0)
{
int tmp1 = cipherText.length() / 8 * 8;
int tmp2 = cipherText.length() - tmp1;
memset(inputText, 0, 8);
memcpy(inputText, cipherText.c_str() + tmp1, tmp2);
DES_ecb_encrypt(&inputText, &outputText, &keySchedule, DES_DECRYPT);// 解密函數
memcpy(tmp, outputText, 8);
for (int j = 0; j < 8; j++)
vecCleartext.push_back(tmp[j]);
}
clearText.clear();
clearText.assign(vecCleartext.begin(), vecCleartext.end());
return clearText;
}
// ---- rsa非對稱加解密 ---- //
#define KEY_LENGTH 2048 // 密鑰長度
#define PUB_KEY_FILE "pubkey.pem" // 公鑰路徑
#define PRI_KEY_FILE "prikey.pem" // 私鑰路徑
// 函數方法生成密鑰對
void generateRSAKey(std::string strKey[2])
{
// 公私密鑰對
size_t pri_len;
size_t pub_len;
char *pri_key = NULL;
char *pub_key = NULL;
// 生成密鑰對
RSA *keypair = RSA_generate_key(KEY_LENGTH, RSA_3, NULL, NULL);
BIO *pri = BIO_new(BIO_s_mem());
BIO *pub = BIO_new(BIO_s_mem());
PEM_write_bio_RSAPrivateKey(pri, keypair, NULL, NULL, 0, NULL, NULL);
PEM_write_bio_RSAPublicKey(pub, keypair);
// 獲取長度
pri_len = BIO_pending(pri);
pub_len = BIO_pending(pub);
// 密鑰對讀取到字符串
pri_key = (char *)malloc(pri_len + 1);
pub_key = (char *)malloc(pub_len + 1);
BIO_read(pri, pri_key, pri_len);
BIO_read(pub, pub_key, pub_len);
pri_key[pri_len] = '\0';
pub_key[pub_len] = '\0';
// 存儲密鑰對
strKey[0] = pub_key;
strKey[1] = pri_key;
// 存儲到磁盤(這種方式存儲的是begin rsa public key/ begin rsa private key開頭的)
FILE *pubFile = fopen(PUB_KEY_FILE, "w");
if (pubFile == NULL)
{
assert(false);
return;
}
fputs(pub_key, pubFile);
fclose(pubFile);
FILE *priFile = fopen(PRI_KEY_FILE, "w");
if (priFile == NULL)
{
assert(false);
return;
}
fputs(pri_key, priFile);
fclose(priFile);
// 內存釋放
RSA_free(keypair);
BIO_free_all(pub);
BIO_free_all(pri);
free(pri_key);
free(pub_key);
}
// 命令行方法生成公私鑰對(begin public key/ begin private key)
// 找到openssl命令行工具,運行以下
// openssl genrsa -out prikey.pem 1024
// openssl rsa - in privkey.pem - pubout - out pubkey.pem
// 公鑰加密
std::string rsa_pub_encrypt(const std::string &clearText, const std::string &pubKey)
{
std::string strRet;
RSA *rsa = NULL;
BIO *keybio = BIO_new_mem_buf((unsigned char *)pubKey.c_str(), -1);
// 此處有三種方法
// 1, 讀取內存裏生成的密鑰對,再從內存生成rsa
// 2, 讀取磁盤裏生成的密鑰對文本文件,在從內存生成rsa
// 3,直接從讀取文件指針生成rsa
RSA* pRSAPublicKey = RSA_new();
rsa = PEM_read_bio_RSAPublicKey(keybio, &rsa, NULL, NULL);
int len = RSA_size(rsa);
char *encryptedText = (char *)malloc(len + 1);
memset(encryptedText, 0, len + 1);
// 加密函數
int ret = RSA_public_encrypt(clearText.length(), (const unsigned char*)clearText.c_str(), (unsigned char*)encryptedText, rsa, RSA_PKCS1_PADDING);
if (ret >= 0)
strRet = std::string(encryptedText, ret);
// 釋放內存
free(encryptedText);
BIO_free_all(keybio);
RSA_free(rsa);
return strRet;
}
// 私鑰解密
std::string rsa_pri_decrypt(const std::string &cipherText, const std::string &priKey)
{
std::string strRet;
RSA *rsa = RSA_new();
BIO *keybio;
keybio = BIO_new_mem_buf((unsigned char *)priKey.c_str(), -1);
// 此處有三種方法
// 1, 讀取內存裏生成的密鑰對,再從內存生成rsa
// 2, 讀取磁盤裏生成的密鑰對文本文件,在從內存生成rsa
// 3,直接從讀取文件指針生成rsa
rsa = PEM_read_bio_RSAPrivateKey(keybio, &rsa, NULL, NULL);
int len = RSA_size(rsa);
char *decryptedText = (char *)malloc(len + 1);
memset(decryptedText, 0, len + 1);
// 解密函數
int ret = RSA_private_decrypt(cipherText.length(), (const unsigned char*)cipherText.c_str(), (unsigned char*)decryptedText, rsa, RSA_PKCS1_PADDING);
if (ret >= 0)
strRet = std::string(decryptedText, ret);
// 釋放內存
free(decryptedText);
BIO_free_all(keybio);
RSA_free(rsa);
return strRet;
}
int main(int argc, char **argv)
{
// 原始明文
std::string srcText = "this is an example";
std::string encryptText;
std::string encryptHexText;
std::string decryptText;
std::cout << "=== 原始明文 ===" << std::endl;
std::cout << srcText << std::endl;
// md5
std::cout << "=== md5哈希 ===" << std::endl;
md5(srcText, encryptText, encryptHexText);
std::cout << "摘要字符: " << encryptText << std::endl;
std::cout << "摘要串: " << encryptHexText << std::endl;
// sha256
std::cout << "=== sha256哈希 ===" << std::endl;
sha256(srcText, encryptText, encryptHexText);
std::cout << "摘要字符: " << encryptText << std::endl;
std::cout << "摘要串: " << encryptHexText << std::endl;
// des
std::cout << "=== des加解密 ===" << std::endl;
std::string desKey = "12345";
encryptText = des_encrypt(srcText, desKey);
std::cout << "加密字符: " << std::endl;
std::cout << encryptText << std::endl;
decryptText = des_decrypt(encryptText, desKey);
std::cout << "解密字符: " << std::endl;
std::cout << decryptText << std::endl;
// rsa
std::cout << "=== rsa加解密 ===" << std::endl;
std::string key[2];
generateRSAKey(key);
std::cout << "公鑰: " << std::endl;
std::cout << key[0] << std::endl;
std::cout << "私鑰: " << std::endl;
std::cout << key[1] << std::endl;
encryptText = rsa_pub_encrypt(srcText, key[0]);
std::cout << "加密字符: " << std::endl;
std::cout << encryptText << std::endl;
decryptText = rsa_pri_decrypt(encryptText, key[1]);
std::cout << "解密字符: " << std::endl;
std::cout << decryptText << std::endl;
system("pause");
return 0;
}