HOW ARE THE VOTING MACHINES SECURED????

A question that comes to mind is how are voting machines used in the early voting being secured at night? With as many people having keys as I am told there seems to be a serious lack of security at the voting place.
With the tremendous impact that early voting has had on elections in recent years it would seem the utmost care should be given to securing these machines which have been proven to be so easily altered by those with minimal computer skills.
We have seen on a National level how elections are stolen when there are no paper trails and even when there are. I would certainly hate to think that an election would be altered not by the voters but by one or two people with a key and the skill to reprogram a voting machine. Allen Barrett