It's total nonsense to be concerned that the SSDI is a source of SSNs that are usable by terrorists. The only thing unique about the SSNs in the SSDI is that the original holders are deceased and the numbers were/are legitimate. Otherwise to the layman any series of numbers laid out in the nnn-nn-nnnn format appears to be legitimate. The issue may be rather any nnn-nn-nnnn appearing on a SSN card. But it is not the number, but rather the appearance on what appears be legitimate SSN card stock that convinces the uniformed not the number itself. As a former employee of SSA I am aware of millions of users of totally bogus numbers for employment purposes. These numbers were identified as belonging to deceased persons, children, adults but mismatched names or were simply made up. The SSDI was not the sources of these SSNs. The existence of the SSDI is irrelevant to anyone who wishes to use a fraudulent number on fake SSN card stock. Indeed each of the SSDI numbers is internally flagged by SSA as not reissuable to anyone for 70 years or so (when in fact they will be recycled to new users). And by the way in Federal matters the deceased do in fact lose their right to privacy upon death. The law is a bit subtler than this of course.