VC6建立OpenSSL AES加密專案

在前一篇Windows下使用VC2010編譯OpenSSL文章中已介紹如何將OpenSSL環境安裝於系統中，這裡將介紹透過VC6建立OpenSSL AES加密專案。
OpenSSL成功Build出來安裝於系統後，在C:\usr\local\ssl路徑下會有bin、include、lib三個資料夾，裡面的檔案就是用來建立加密專案所需Lib與include的路徑，接下來就一步步教大家如何配置檔案至正確路徑，Build出加密App。

開啟VC6建立一新專案TestAES。

1. 設定OpenSSL Lib、Include路徑
Tools -> Options -> Directories -> Show directories for: Include files
加入C:\usr\local\ssl\include
Tools -> Options -> Directories -> Show directories for: Library files
加入C:\usr\local\ssl\lib


2. 將C:\usr\local\ssl\bin或C:\openssl\out32dll下的libeay32.dll、ssleay32.dll複製到到C:\Windows\system32下。


3. 將以下Linker加入專案擋頭。

#pragma comment(lib, "libeay32.lib") 
#pragma comment(lib, "ssleay32.lib") 

4. 編譯執行以下程式碼。

#include <openssl/aes.h>
#include <openssl/rand.h>
#pragma comment(lib, "libeay32.lib") 
#pragma comment(lib, "ssleay32.lib") 

UCHAR CEKKey[AES_BLOCK_SIZE];  
UCHAR IVKey[AES_BLOCK_SIZE]; 

void aes_create_key()
{
 //CEK Key
 RAND_bytes(CEKKey, sizeof(CEKKey));

 //IV key
 RAND_bytes(IVKey, sizeof(IVKey));
}

BOOL aes_encrypt(char* source_string, UCHAR* des_string)  
{
 int nLen =0;
 AES_KEY aes;
 UCHAR key[AES_BLOCK_SIZE];
 UCHAR iv[AES_BLOCK_SIZE];

 memcpy(key, CEKKey, 16);
 memcpy(iv, IVKey, 16);
 
 if(NULL == source_string || NULL == des_string)
  return FALSE;
 
 if (AES_set_encrypt_key(key, 128, &aes) < 0)
  return FALSE;

 nLen = strlen(source_string)+1;
 
 AES_cbc_encrypt((UCHAR*)source_string, des_string, nLen, &aes, iv, AES_ENCRYPT);

 return TRUE;
}  

BOOL aes_decrypt(char* source_string, UCHAR* des_string)  
{
 int nLen =0;
 AES_KEY aes;
 UCHAR key[AES_BLOCK_SIZE];
 UCHAR iv[AES_BLOCK_SIZE];

 memcpy(key, CEKKey, 16);
 memcpy(iv, IVKey, 16);
 
 if(NULL == source_string || NULL == des_string)
  return FALSE;
 
 if (AES_set_decrypt_key(key, 128, &aes) < 0)
  return FALSE;
 
 nLen = strlen(source_string)+1;
 
 AES_cbc_encrypt((UCHAR*)source_string, des_string, nLen, &aes, iv, AES_DECRYPT);
 
 return TRUE;
}

int main(int argc, TCHAR* argv[], TCHAR* envp[])
{
 CHAR cSource[] = {"Hello!AminWhite"};
 UCHAR cDstStringTemp[16+1] = {0};
 UCHAR ucDst[16+1] = {0};
 
 aes_create_key();
 
 aes_encrypt(cSource, cDstStringTemp);
 
 printf("Encrypt text : %s\n", cSource); 
 printf("After Encrypt: %s\n", cDstStringTemp);
 
 aes_decrypt((CHAR*)cDstStringTemp, ucDst);
 
 printf("Decrypt text : %s\n", ucDst);
 
 return TRUE;
}

執行畫面：