在Objective-C中使用SHA1 Hash of Torrent文件的问题

Due to the inadequacies of µTorrent's response system when sending through either magnet links or torrent files, that is, the complete lack of a message for duplicate torrent adding, I am attempting to get the hash from a torrent file before it's sent over and comparing that with the list of current jobs. The code I currently have is returning an incorrect hash and I haven't a clue why. Here is the code I'm using.Due to the inadequacies of µTorrent's response