Question: I recently found [Mouse without Borders](https://www.microsoft.com/en-us/download/details.aspx?id=35460) but this just works for Windows.

My question is now if there is something like that which works with Ubuntu with a secure connection.  

It should provide

* Mouse sharing
* keyboard sharing
* Clipboard sharing
* secure (encrypt data)

If possible for free.  

I would appreciate OpenSource

Answer: 
Definitely possible for free, out-of-the-box in Ubuntu:

```
sudo apt-get install synergy

```

This software comes from the Ubuntu repositories and is free, open source and has all the needed (at least for me) properties (at least for 14.04 LTE).

---

And to complete the answer:

This command is better to use when installing, because it does not let you install stuff unless you have your repos up to date:

```
sudo apt-get update && sudo apt-get install synergy

```

and this gives you a clue on what is available in the repos you have configured on your machine:

```
apt-cache search synergy

```

As long as 16.04 LTE, standard repos are considered:

```
quicksynergy - GUI for easy configuration of Synergy
synergy - Share mouse, keyboard and clipboard over the network

```
Try with Barrier-KVM. This works perfectly for me. You can also use this with different subnets and different OS Platforms.