2003 Chevrolet Malibu

My 2003 Chevrolet Malibu is blessed to have a “theft system” on the vehicle, when I first purchase the car it wouldnt start from time to time until the car recognized the key this last about a month and would only do it occassionally, then it did not happen again for 3 years. Now all of a sudden it is doing it again and I am using the same key, it is also doing to more often then it did originally? what is happening? the only person it is keeping from operating the vehicle is me the owner???

sometimes the key hole will get dirty and not regonize the computer chip in the key try cleaning the barrel with a solvent.