hello,
i created security in minecraft.
but not only that, i made it with one command block. :)
you can find the command here:

http://pastebin.com/ZtMRTugu

i hope you will try this out !


here are the things you have:

1) mine:
 you can place this mine on the ground and whenever someone steps over it it explodes.

2) electric fence
these are iron bars but they are charged with electricity, if you walk into it you will hurt yourself.

3) turret
this turret will 2 hit-kill zombies, creepers, skeletons and spiders in a 3 block range

4) alarm
this thing will make noice if it detects zombies, skeletons, spiders, endermans and creepers.

5) locker
this is just a locker that you can only open with a key.