使用 FileSource 加密内容后无法删除文件

Question

我正在尝试使用 AES EAX 模式和 CryptoPP 库加密文件。这是 main() 的内容：

SecByteBlock key(AES::MAX_KEYLENGTH);
rnd.GenerateBlock(key, key.size());
ArraySource as(key.begin(), key.size(), true, new FileSink("key.bin"));

SecByteBlock iv(AES::BLOCKSIZE);
rnd.GenerateBlock(iv, AES::BLOCKSIZE);

EAX<AES>::Encryption encryptor;
encryptor.SetKeyWithIV(key, key.size(), iv, iv.size());

FileSink file("image.jpg.enc");

ArraySource write_iv(iv, iv.size(), true, new Redirector(file));

FileSource write_ciphertext("image.jpg", true, new AuthenticatedEncryptionFilter(encryptor, new Redirector(file)));

const int delete_file = std::remove("image.jpg");
std::cout << delete_file << std::endl;
std::cout << "Error code is:" << GetLastError();

return 0;

加密部分成功结束，然而，删除原始文件（image.jpg）fails.The我得到的输出是：

Error code is:32

这是一个ERROR_SHARING_VIOLATION，意思是"The process cannot access the file because it is being used by another process." 我的问题是：如何在 Filesource 行之后关闭文件，以便能够删除之后的文件？对于经典的 ifstream ，它将是 file.close()，但我如何使用 Crypto++ 做到这一点？

Answer 1

我不熟悉 crypto++，但如果他们遵循 RAII 模式，那么触发 ~FileSource 析构函数应该足以关闭文件句柄。

在 C++ 中，您将使用匿名作用域来定义自动变量的生命周期。匿名范围使用大括号定义，不带任何关键字：

using namespace std;
...
encryptor.SetKeyWithIV(key, key.size(), iv, iv.size());

// begin an anonymous scope:
{

    FileSink    file             ( "image.jpg.enc" );
    ArraySource write_iv         ( iv, iv.size(), true, new Redirector( file ) );
    FileSource  write_ciphertext ( "image.jpg", true, new AuthenticatedEncryptionFilter( encryptor, new Redirector( file ) ) );        
}
// end the scope, causing all objects declared within to have their destructors called

const int delete_file = remove("image.jpg");
cout << delete_file << endl;
cout << "Error code is:" << GetLastError();
...

顺便说一句，我注意到你使用了 new 而没有使用 delete。我相信您可以使这些参数对象也自动生成，如下所示：

using namespace std;
...
encryptor.SetKeyWithIV(key, key.size(), iv, iv.size());

// begin an anonymous scope:
{       
    FileSink                      file            ( "image.jpg.enc" );
    Redirector                    write_redir     ( file );
    ArraySource                   write_iv        ( iv, iv.size(), true, &write_redir );
    AuthenticatedEncryptionFilter filter          ( encryptor, &write_redir )
    FileSource                    write_ciphertext( "image.jpg", true, &filter );
}
// end the scope, causing all objects declared within to have their destructors called

const int delete_file = remove("image.jpg");
cout << delete_file << endl;
cout << "Error code is:" << GetLastError();
...

使用 FileSource 加密内容后无法删除文件

Can't delete file after encrypting content with FileSource

c++

windows

encryption

crypto++