User blog comment:ShadowRezza/How would i set the computer so that i type in a password and the door to my house opens?/@comment-5266265-20120716122328

This a tutorial which may explain quite a bit: http://www.minecraftforum.net/topic/907632-mod-tutorial-computercraft-v12-very-basic-lua-tutorial-updated-1112/page__p__11556908#entry11556908

And this is the locked door: http://www.minecraftforum.net/topic/954835-mod-tutorial-computercraft-how-to-make-a-locked-door-11812/