Was away for a day and just read your reply. I forwarded it on to an NT consultant I know. He replied back with the following:

"Yup... they have had these for a while, they typically have a small client
that retrieves instruction sets from another machine to process key/hash
patterns to crack encryption algorhhytms and send the results back which
would normally take centuries. (sp?) And if your computer cracks it, you
get $1000 or so in cash. I think they just cracked 56 or 64bit encryption
which supposedly couldnt be cracked for years, they are probably working on
128bit now. They also have a client screen saver that is for SETI
processing in the search for extraterrestrial life. As far as the CPU usage, they are designed to NOT interfere with the machine, but they frequently kill the CPU and lock up, etc etc.... "

Thought you might find this interesting. BTW, this isn't some "Forward this to at least 100 people and Bill Gates will send you a $1,000" deals. The source for this is VERY reliable in my book. He went on to say be careful running a client like this on any box.