Sunday, March 19, 2006

Bugs and dust

This may not be a “post,” more like a semi-post -- musings on two uses of microelectromechanical sensors (MEMs) that are in varying states of development.

MEMs are mechanical devices that range in size from a micrometer to a millimeter and are manufactured using any of several different technologies. MEMs have many hypothesized uses, but I want to focus on two which illustrate how advances in technology can erode privacy in ways we have never before had to think about.

One hypothesized use of MEMs is to create “smart dust.” The notion of smart dust has been around for years, but developers are increasingly on their way to making it a reality. Basically, smart dust is a network of MEMs devices “installed with wireless communications, that can detect anything from light and temperature, to vibrations, etc.” “Smart Dust,” Wikipedia.The ultimate goal of those engaged in developing smart dust is to “combine communication, computation, and sensing into a single tiny package.” The smart dust motes would be able to communicate not only with a base station operated by humans, but with each other; the dust motes would become a distributed computer network with, some contend, a distributed intelligence comparable to that found among ants, bees or other social insects.

Smart dust could be scattered around a building or other area where it could track the movements of individuals and/or detect the presence of chemicals or other noteworthy substances. Smart dust motes could also be released into the atmosphere inside a building or other structure; the motes would be light enough to float and would be, for all intents and purposes, indistinguishable from regular dust motes. Unlike regular dust motes, however, the smart dust motes would be collecting information from inside the building and sharing that information with an external base station manned by humans.

The other, far-more hypothetical use of MEMs is to create “insect cyborgs” by implanting MEMs into moths and other insects. The MEMs would be surgically implanted when the insects are in the pupa stage of their development, midway between the larval and adult stages. The premise is that the insects would adapt their maturation process to accommodate the implanted MEMs, which would let human operators control the adult insects. Those engaged in this effort believe operators would be able to used the MEM-modified insects to detect bombs or other chemicals. They also believe the human operators would be able to control the insects’ movements, so that they could, for example, be directed to a particular location to monitor explosives or even human activities.

Both of these scenarios raise interesting, and disconcerting, possibilities for circumventing our ability to maintain our privacy. As I have explained elsewhere, privacy has historically been a bricks-and-mortar concept; our Fourth Amendment, for example, derives from the English maxim that "a man's home is his castle." It is this reverence for the privacy of a particular place, notably the home, that has led our Supreme Court to observe on numerous occasions that "the Fourth Amendment has drawn a firm line at the entrance to the house. Absent exigent circumstances, that threshold may not . . . be crossed without a warrant." Payton v. New York, 445 U.S. 573 (1980).

The Supreme Court was, of course, talking about the threshold's being crossed by police, not about what might drift in on air currents.

As I explained in an earlier post ("Cartapping," February 21, 2006), under the Katz test, the test the Supreme Court uses to implement Fourth Amendment privacy guarantees, I will
  • have a Fourth Amendment expectation of privacy in a place if I take efforts to protect that place from being "invaded" by law enforcement officers; and
  • not have such an expectation if I do not effectively protect that place from being "invaded" by law enforcement officers.
So, as I explain to my students, I have a Fourth Amendment expectation of privacy in what occurs inside my home if I close the doors, close the curtains and otherwise protect the interior of my home from observations by members of the public and/or law enforcement officers who are physically located in the public areas outside my home.

How do we apply this test to smart dust and insect cyborgs? Does it mean that to have a Fourth Amendment expectation of privacy do I have to completely eradicate dust and insects from my home? We all, of course, make an effort to eliminate dust and insects, but until now that was a product of our desire for cleanliness and sanitation . . . not a matter of constitutional import.

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