On My Mind
They're Watching
Bruce Schneier 01.08.07, 12:00 AM ET

If you read this piece we'll have to kill you.

If you've traveled abroad recently, you've been investigated. You've been assigned a score indicating what kind of terrorist threat you pose. That score is used by the government to determine the treatment you receive when you return to the U.S. and for other purposes as well.

Curious about your score? You can't see it. Interested in what information was used? You can't know that. Want to clear your name if you've been wrongly categorized? You can't challenge it. Want to know what kind of rules the computer is using to judge you? That's secret, too. So is when and how the score will be used.

U.S. customs agencies have been quietly operating this system for several years. Called Automated Targeting System, it assigns a "risk assessment" score to people entering or leaving the country, or engaging in import or export activity. This score, and the information used to derive it, can be shared with federal, state, local and even foreign governments. It can be used if you apply for a government job, grant, license, contract or other benefit. It can be shared with nongovernmental organizations and individuals in the course of an investigation. In some circumstances private contractors can get it, even those outside the country. And it will be saved for 40 years.

Little is known about this program. Its bare outlines were disclosed in the Federal Register in October. We do know that the score is partially based on details of your flight record--where you're from, how you bought your ticket, where you're sitting, any special meal requests--or on motor vehicle records, as well as on information from crime, watch-list and other databases.

Civil liberties groups have called the program Kafkaesque. But I have an even bigger problem with it. It's a waste of money.

The idea of feeding a limited set of characteristics into a computer, which then somehow divines a person's terrorist leanings, is farcical. Uncovering terrorist plots requires intelligence and investigation, not large-scale processing of everyone.

Additionally, any system like this will generate so many false alarms as to be completely unusable. In 2005 Customs & Border Protection processed 431 million people. Assuming an unrealistic model that identifies terrorists (and innocents) with 99.9% accuracy, that's still 431,000 false alarms annually.

The number of false alarms will be much higher than that. The no-fly list is filled with inaccuracies; we've all read about innocent people named David Nelson who can't fly without hours-long harassment. Airline data, too, are riddled with errors.

The odds of this program's being implemented securely, with adequate privacy protections, are not good. Last year I participated in a government working group to assess the security and privacy of a similar program developed by the Transportation Security Administration, called Secure Flight. After five years and $100 million spent, the program still can't achieve the simple task of matching airline passengers against terrorist watch lists.

In 2002 we learned about yet another program, called Total Information Awareness, for which the government would collect information on every American and assign him or her a terrorist risk score. Congress found the idea so abhorrent that it halted funding for the program. Two years ago, and again this year, Secure Flight was also banned by Congress until it could pass a series of tests for accuracy and privacy protection.

In fact, the Automated Targeting System is arguably illegal, as well (a point several congressmen have made recently); all recent Department of Homeland Security appropriations bills specifically prohibit the department from using profiling systems against persons not on a watch list.

There is something un-American about a government program that uses secret criteria to collect dossiers on innocent people and shares that information with various agencies, all without any oversight. It's the sort of thing you'd expect from the former Soviet Union or East Germany or China. And it doesn't make us any safer from terrorism.

Bruce Schneier, Chief Technology Officer of BT Counterpane, which manages security for corporate clients.