Co-authored by Patrick Mutchler.
Is telephone metadata sensitive? The debate has taken on new urgency since last summer’s NSA revelations; all three branches of the federal government are now considering curbs on access. Consumer privacy concerns are also salient, as the FCC assesses telecom data sharing practices.
President Obama has emphasized that the NSA is “not looking at content.” “[T]his is just metadata,” Senator Feinstein told reporters. In dismissing the ACLU’s legal challenge, Judge Pauley shrugged off possible sensitive inferences as a “parade of horribles.”
On the other side, a number of computer scientists have expressed concern over the privacy risks posed by metadata. Ed Felten gave a particularly detailed explanation in a declaration for the ACLU: “Telephony metadata can be extremely revealing,” he wrote, “both at the level of individual calls and, especially, in the aggregate.” Holding the NSA’s program likely unconstitutional, Judge Leon credited this view and noted that “metadata from each person’s phone ‘reflects a wealth of detail about her familial, political, professional, religious, and sexual associations.’”
This is, at base, a factual dispute. Is it easy to draw sensitive inferences from phone metadata? How often do people conduct sensitive matters by phone, in a manner reflected by metadata?