How to encrypt data correctly? - c++

Question

I have the following code. I'd like to add to this code a key BYTE[] and an IV BYTE[] too, to encrypt my data with. To do that i have to call CryptImportKey and CryptSetKeyParam.
So my questions are:
Where do i have to call theese two APIs? I think after CryptDeriveKey, and then use the output from CryptImportKey to encrypt my data. Am i right?
Can i somehow ensure that the result is correct encrypted? Should i make some other changes to make my code more secure?
#include <string>
#include <iostream>
using namespace std;
struct CryptStuff
{
HCRYPTPROV* hProv;
HCRYPTKEY* hKey;
HCRYPTHASH* hHash;
CryptStuff(HCRYPTPROV* hprov, HCRYPTKEY* hkey, HCRYPTHASH* hash) :
hProv(hprov), hKey(hkey), hHash(hash) {}
~CryptStuff()
{
if ( *hKey ) CryptDestroyKey( *hKey );
if ( *hHash ) CryptDestroyHash( *hHash );
if ( *hProv ) CryptReleaseContext( *hProv, 0 );
}
};
void EncryptData( TCHAR *lpszPassword, char *pbBuffer, DWORD *dwCount )
{
HCRYPTPROV hProv = 0;
HCRYPTKEY hKey = 0;
HCRYPTHASH hHash = 0;
// create an instance of CryptStuff. This will cleanup the data on return
CryptStuff cs(&hProv, &hKey, &hHash);
LPWSTR wszPassword = lpszPassword;
DWORD cbPassword = ( wcslen( wszPassword ) + 1 )*sizeof( WCHAR );
if ( !CryptAcquireContext( &hProv, NULL, MS_ENH_RSA_AES_PROV, PROV_RSA_AES,
CRYPT_VERIFYCONTEXT ) )
{
return;
}
if ( !CryptCreateHash( hProv, CALG_SHA_256, 0, 0, &hHash ) )
{
return;
}
if ( !CryptHashData( hHash, ( PBYTE )wszPassword, cbPassword, 0 ) )
{
return;
}
if ( !CryptDeriveKey( hProv, CALG_AES_256, hHash, CRYPT_EXPORTABLE, &hKey ) )
{
return;
}
DWORD size = ( DWORD )strlen( pbBuffer ) / sizeof( char );
cout << "\nLength of string = " << size;
if ( !CryptEncrypt( hKey, 0, TRUE, 0, ( LPBYTE )pbBuffer, &size, BLOCK_SIZE ) )
{
return;
}
cout << "\nEncrypted bytes = " << size;
cout << "\nEncrypted text = ";
cout.write(pbBuffer, size);
if ( !CryptDecrypt( hKey, 0, TRUE, 0, ( LPBYTE )pbBuffer, &size ) )
{
return;
}
cout << "\nDecrypted bytes = " << size;
cout << "\nDecrypted text = ";
cout.write(pbBuffer, size);
}
Thanks in advance!