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I'm writing an application for controlling computers from a client.

I'd very much like it if the connection is secure and only authenticated clients are allowed access.

The workflow will be something like this:

  1. A client use decides to add the server
  2. The server allows the client
    1. Alternative 1; On the server screen a X digit code is displayed that the client has to enter.
    2. Alternative 2; The server presents a dialog which the server user has to accept.
  3. The client and server exchanges keys to remember each other.

I understand that this initial communication won't be 100% secure unless the user manually verifies it, what's important is that future communications are secure.

What are good ways to make this as secure as possible?
None of the data sent is ATM sensitive so as a worst case only authentication is required.

If possible I would like to use HTTP(S) as the protocol.

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up vote 3 down vote accepted

What you are looking for is how to implement an SSL/TLS layer on top of your TCP connection. Try to use the OpenSSL library, it's the most popular implementation.

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So I guess the client would fetch the remote certificate and store it to verify the server while the client will add some secret to the server which it uses to verify the client. – Nicklas Ansman Jan 20 '14 at 10:16
The certificate verification can be handled by the container/framework you're working on. For instance, in Java it's been done by the trustManager, here is a nice Java SSL/TLS implementation example – theofpa Jan 20 '14 at 12:52

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