Editor: When you get an archive with a piece of software or some documents for some of us (and maybe even you) it is important to know if the archive is the original one and no one has modified it on its way to you.
The simplest way to do that is to determine a "signature" or "hash" of that file. You then compare the hash you have determined with the hash you can see on the site where the original files is stored. If the two hashes are different then you can know for sure that your copy of the file is not a copy of the original one! If the two hashes are equal then you may have a correct copy. You can not be 100% sure, but there is a very small probability that two different files will have the same hash.
