Like I've said before, nothing in this world is 100% secure, and there is no cable that cannot be tapped. Copper cables are easy to tap into, and some people think that fiber is immune to tapping, but they're wrong - it just requires a procedure which is a bit more complicated. I'm going to bring here some details about it, so that you may get an idea of how to defend against these taps.

Here's how it can be done: the first thing the hacker needs to do is find the cable and, without being detected, he has to remove the jacket as well as the cladding, to leave the fiber "naked". Optical fiber is used to transmit light, and as Wikipedia explains things, it guides the light along its length by confining as much light as possible in a propagating form. If you understand that, then you already know what the hacker needs to do next. Once he has access to the bare cable, he needs to bend it, that's when the light will leak out of the cable. Then, the hacker has to get the light projected upon a surface that is able to transmit it even further. The device that "catches" the light then transmits it to another gizmo that converts optical information into electrical data. It's all down hill from that point. All the hackers needs to do then is connect the last converting device to a computer and that's it - he's wiretapping you!

Now, here's how you can avoid this - a lot of cyber-security is enforced with non-cyber measures. In this case, for the hacker to wiretap the cable, he needs to have access to it, so place your cables in such a way that they cannot be reached by anyone with malicious intentions. If that is too hard or impossible to do, then make sure you know what's happening with your cables. If you cannot deploy security cameras, then install a device that will alert you if anything changes in the way information goes through the cable. So, now you know - don't complain if you get tapped!