Question

I want to transfer a big file between server and client, I know how to do this:
for the client side, the code is like :

OutputStream output = sk.getOutputStream();     

    FileInputStream fileInputStream = new FileInputStream(file);
    byte[] buffer = new byte[1024*1024];
    int bytesRead = 0;

    while((bytesRead = fileInputStream.read(buffer))>0)
    {
        output.write(buffer,0,bytesRead);
    }

    fileInputStream.close();

for server side:

InputStream input = sk.getInputStream();

    file = new File(filename);
    FileOutputStream out = new FileOutputStream(file);

    byte[] buffer = new byte[1024*1024];

    int bytesReceived = 0;

    while((bytesReceived = input.read(buffer))>0) {
        out.write(buffer,0,bytesReceived);
        System.out.println(bytesReceived);
        break;
    }

Now the problem is, the server and client agree on a 128-bit AES key, so I want to make fully use of the session key to make the file transfer process secure. My question is that, where can I insert the AES encryption process in my client and server? Thank you!

Answer 1

I think you could use javax.crypto.CipherInputStream / javax.crypto.CipherOutputStream. Usage example http://www.flexiprovider.de/examples/ExampleCrypt.html