Recently there has been a wave of program "releases" that claim they can decrypt black ops fastfiles. These programs are fake, and most likely contain malware.
Please note, currently there is no public method for decrypting fastfiles.
Tools you can trust:
CPMonkey's FastCryptTool
iHc ZoneViewer
iHc Toolbox
Tools you can NOT trust:
Any tool claiming to be a "black ops version of ffviewer"
Next, there has also been a wave of viruses claiming they can edit your black ops rank, cod points etc. These are all fake, and 100% viruses. You can not mod your black ops rank from your PC.
Tools you can trust:
NONE!
Tools you can NOT trust:
Any tool claiming to edit your black ops prestige, rank, or cod points (etc..)
Any tool claiming to edit blackops savegame.svg's
Any tool claiming to give you infections
etc.. (use common sense)