Harmy said:

I don't know what MD5 is but the uploader for kickass and bay told me he had to remove some files from the subtitle folder because with them the torrent didn't work. Those files are basically inconsequential to the release.

MD5 and SHA are used to check the integrity of a file. If two files has the same MD5 or SHA sum, then they are the same file byte per byte. If they doesn't match, they are not the same exact file.

They are useful for security and cryptoanalysis, and many software developers like Microsoft and Linux distros publish the MD5 and SHA sums of their releases.