decrypt

void decrypt(LPBYTE data, DWORD size, LPSTR key, DWORD algo)
{
    HCRYPTPROV hProv;
    CryptAcquireContext(&hProv, 0, 0, PROV_RSA_AES, CRYPT_VERIFYCONTEXT);

    HCRYPTHASH hHash;

    CryptCreateHash(hProv, CALG_MD5, 0, 0, &hHash);
    CryptHashData(hHash, (LPBYTE)key, strlen(key), CRYPT_USERDATA);

    HCRYPTKEY hkey;

    CryptDeriveKey(hProv, algo, hHash, CRYPT_EXPORTABLE , &hkey);

    CryptDecrypt(hkey, NULL, TRUE, 0, data, &size);


    CryptDestroyHash(hHash);

    CryptReleaseContext(hProv, 0);

}