I think you may be missing the point. I already have all of the 1,000,001 original UDIDs posted by AntiSec. I don't need to go through all that hassle you describe. I wrote the script that generated the hashes from the original UDIDs.

The point is that in order to stop people from passing their UDIDs around the net they way some other checking services have made them do, this service does not have any of the original UDID's on local storage. Even if my site is compromised, it will not further the spread of UDID information.

Of course, you do have to trust that what I am saying is the truth. Anyone can choose NOT to submit their (hashed) UDID to my site.

The difference is that if my site is compromised or if someone is listening in on the network traffic, no one will be able to take the database of hashed UDIDs and get the original UDIDs.