There are things you should know.

Security is a game that is always the same.  If you get a bigger lock
someone gets a bigger hammer.  This escalation continues until someone runs
out of time or money to continue the game.

Nothing is secure.  It is not possible to have perfect security.  Ultimately
you are the most insecure part of any system.

When two systems communicate security is lost.  It is like a secret.  Once
you tell it, it is no longer a secret.  That being said, it is possible to
have secure communication between two systems but the weakest points of that
communication are the endpoints.  This is true especially of encryption. 
Why would you go to the effort to try to decrypt the data when you could
simply monitor the endpoints where the users are decrypting it for you?

Generally speaking the more you attempt to secure a system the more
difficult it becomes to use.  You can make a system completely unusable
trying to secure it.  But at the same time people are incredibly lazy and
seem to refuse to make an effort to learn the methods which would secure
their system from most riffraff.  We always seem to take the easy way out
rather than take the road that though more difficult will be better in the
long run.  We are incredibly short sited.  Computer systems do not have this
problem.  They are relentless and once you set them going they will operate
in a tenacious manner that people cannot keep up with.  If you leave a
little tiny hole in your system it will eventually be found.  Thinking that
on one will find it might well be true but you're not hiding it from a
person you're hiding it from a methodical, relentless, tireless foe... 
10000 computers.