I think that the author is Jorge Luis Borges, but I was looking for his short stories on the internet and I didn't find a short story from him about the aliens and matchstick.
More or less the short story is about the first contact of aliens with humanity and they ask for the whole of human knowledge. The people give them the Encyclopedia Britannica. The aliens say that the books are too big, and with a precision machine put a mark in a matchstick. The mark is a number representing the "compressed" texts of all books.