Entries Tagged "full-body scanners"

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Yet Another Way to Evade TSA's Full-Body Scanners

Last night, at the Third EPIC Champion of Freedom Awards Dinner, we gave an award to Susie Castillo, whose blog post and video of her treatment in the hands of the TSA has inspired thousands to complain about the agency and their treatment of travellers.

Sitting with her at dinner, I learned yet another way to evade the TSA’s full body scanners: carry a small pet. She regularly travels with her small dog, and has found that she is always directed away from the full-body scanners and through the magnetometers. I suspect that the difficulty of keeping the dog still is why TSA makes that determination. (The carrier, of course, goes through the x-ray machine.)

I’m not sure what the TSA is going to do now that I’ve publicized this unpublished exception. Those of you who travel with small pets: please let me know what happens.

(For those of you who are appalled that I could give the terrorists ideas on how to evade the full-body scanners, there are already so many ways that one more can’t hurt.)

Posted on June 14, 2011 at 7:54 AMView Comments

New Airport Scanning Technology


Iscon’s patented, thermo-conductive technology combines infrared (IR) and heat transfer, for high-resolution imaging without using any radiation. The core of this is state of the art imaging which detects and processes a break in the established thermal balance between the clothes and a hidden object. The IR camera detects the heat radiating from even a tiny object, producing a dark/light shape. It is irrelevant how long an object is concealed under clothing as a new temperature imprint is created every time it is scanned. Using IR, the rays don’t penetrate beyond the clothing so there are no privacy issues.

EDITED TO ADD (6/14): Another article.

I know no details.

Posted on June 10, 2011 at 6:14 AMView Comments

Cost-Benefit Analysis of Full-Body Scanners

Research paper from Mark Stewart and John Mueller:

The Transportation Security Administration (TSA) has been deploying Advanced Imaging Technologies (AIT) that are full-body scanners to inspect a passenger’s body for concealed weapons, explosives, and other prohibited items. The terrorist threat that AITs are primarily dedicated to is preventing the downing of a commercial airliner by an IED (Improvised Explosive Device) smuggled on board by a passenger. The cost of this technology will reach $1.2 billion per year by 2014. The paper develops a cost-benefit analysis of AITs for passenger screening at U.S. airports. The analysis considered threat probability, risk reduction, losses, and costs of security measures in the estimation of costs and benefits. Since there is uncertainty and variability of these parameters, three alternate probability (uncertainty) models were used to characterise risk reduction and losses. Economic losses were assumed to vary from $2-50 billion, and risk reduction from 5-10%. Monte-Carlo simulation methods were used to propagate these uncertainties in the calculation of benefits, and the minimum attack probability necessary for AITs to be cost-effective was calculated. It was found that, based on mean results, more than one attack every two years would need to originate from U.S. airports for AITs to pass a cost-benefit analysis. In other words, to be cost-effective, AITs every two years would have to disrupt more than one attack effort with body-borne explosives that otherwise would have been successful despite other security measures, terrorist incompetence and amateurishness, and the technical difficulties in setting off a bomb sufficiently destructive to down an airliner. The attack probability needs to exceed 160-330% per year to be 90% certain that AITs are cost-effective.

EDITED TO ADD (1/26): Response from one of the paper’s authors.

Posted on January 20, 2011 at 1:39 PMView Comments

Hiding PETN from Full-Body Scanners

From the Journal of Transporation Security, “An evaluation of airport x-ray backscatter units based on image characteristics,” by Leon Kaufman and Joseph W. Carlson:


Little information exists on the performance of x-ray backscatter machines now being deployed through UK, US and other airports. We implement a Monte Carlo simulation using as input what is known about the x-ray spectra used for imaging, device specifications and available images to estimate penetration and exposure to the body from the x-ray beam, and sensitivity to dangerous contraband materials. We show that the body is exposed throughout to the incident x-rays, and that although images can be made at the exposure levels claimed (under 100 nanoGrey per view), detection of contraband can be foiled in these systems. Because front and back views are obtained, low Z materials can only be reliable detected if they are packed outside the sides of the body or with hard edges, while high Z materials are well seen when placed in front or back of the body, but not to the sides. Even if exposure were to be increased significantly, normal anatomy would make a dangerous amount of plastic explosive with tapered edges difficult if not impossible to detect.

From the paper:

It is very likely that a large (15-20 cm in diameter), irregularly-shaped, cm-thick pancake with beveled edges, taped to the abdomen, would be invisible to this technology, ironically, because of its large volume, since it is easily confused with normal anatomy. Thus, a third of a kilo of PETN, easily picked up in a competent pat down, would be missed by backscatter “high technology”. Forty grams of PETN, a purportedly dangerous amount, would fit in a 1.25 mm-thick pancake of the dimensions simulated here and be virtually invisible. Packed in a compact mode, say, a 1 cm×4 cm×5 cm brick, it would be detected.

EDITED TO ADD (1/12): Stephen Colbert on the issue.

Posted on December 17, 2010 at 2:13 PMView Comments

Alternate Scanning Technologies

Iscon uses infrared light rather than X-rays. I have no idea how well it works.

And Rapiscan has a new patent:


The present invention is directed towards an X-ray people screening system capable of rapidly screening people for detection of metals, low Z materials (plastics, ceramics and illicit drugs) and other contraband which might be concealed beneath the person’s clothing or on the person’s body. In an exemplary embodiment, the scanning system has two scanning modules that are placed in parallel, yet opposing positions relative to each other. The two modules are spaced to allow a subject, such as a person, to stand and pass between the two scanning modules. The first module and second module each include a radiation source (such as X-ray radiation) and a detector array. The subject under inspection stands between the two modules such that a front side of the subject faces one module and the back side of the subject faces the other module.

Posted on December 10, 2010 at 6:22 AMView Comments

Sane Comments on Terrorism

From Michael Leiter, the director of the National Counterterrorism Center:

Ultimately, Leiter said, it’ll be the “quiet, confident resilience” of Americans after a terrorist attack that will “illustrate ultimately the futility of terrorism.” That doesn’t mean not to hit back: Leiter quickly added that “we will hold those accountable [and] we will be ready to respond to those attacks.” But it does mean recognizing, he said, that “we help define the success of an attack by our reaction to that attack.”

Sure, I’ve been saying this since forever. But I think this is the most senior government person who has said this.

EDITED TO ADD (12/8): There are enough essays with this sentiment that I’m going to stop blogging about it. Here’s what I have saved up.

Roger Cohen, “The Real Threat to America“:

So I give thanks this week for the Fourth Amendment: “The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”

I give thanks for Benjamin Franklin’s words after the 1787 Constitutional Convention describing the results of its deliberations: “A Republic, if you can keep it.”

To keep it, push back against enhanced patting, Chertoff’s naked-screening and the sinister drumbeat of fear.

Christopher Hitchens, Don’t Be an Ass About Airport Security.”

Tom Engelhardt, “The National Security State Cops a Feel.”

Evan DeFilippis, “A Nude Awakening — TSA and Privacy“:

If we have both the right to privacy and the right to travel, then TSA´s newest procedures cannot conceivably be considered legal. The TSA´s regulations blatantly compromise the former at the expense of the latter, and as time goes on we will soon forget what it meant to have those rights.

EDITED TO ADD (12/8): Also, this great comic.

Posted on December 8, 2010 at 7:10 AMView Comments

Full Body Scanners: What's Next?

Organizers of National Opt Out Day, the Wednesday before Thanksgiving when air travelers were urged to opt out of the full-body scanners at security checkpoints and instead submit to full-body patdowns — were outfoxed by the TSA. The government pre-empted the protest by turning off the machines in most airports during the Thanksgiving weekend. Everyone went through the metal detectors, just as before.

Now that Thanksgiving is over, the machines are back on and the "enhanced" pat-downs have resumed. I suspect that more people would prefer to have naked images of themselves seen by TSA agents in another room, than have themselves intimately touched by a TSA agent right in front of them.

But now, the TSA is in a bind. Regardless of whatever lobbying came before, or whatever former DHS officials had a financial interest in these scanners, the TSA has spent billions on those scanners, claiming they’re essential. But because people can opt out, the alternate manual method must be equally effective; otherwise, the terrorists could just opt out. If they make the pat-downs less invasive, it would be the same as admitting the scanners aren’t essential. Senior officials would get fired over that.

So not counting inconsequential modifications to demonstrate they’re "listening," the pat-downs will continue. And they’ll continue for everyone: children, abuse survivors, rape survivors, urostomy bag wearers, people in wheelchairs. It has to be that way; otherwise, the terrorists could simply adapt. They’d hide their explosives on their children or in their urostomy bags. They’d recruit rape survivors, abuse survivors, or seniors. They’d dress as pilots. They’d sneak their PETN through airport security using the very type of person who isn’t being screened.

And PETN is what the TSA is looking for these days. That’s pentaerythritol tetranitrate, the plastic explosive that both the Shoe Bomber and the Underwear Bomber attempted but failed to detonate. It’s what was mailed from Yemen. It’s in Iraq and Afghanistan. Guns and traditional bombs are passé; PETN is the terrorist tool of the future.

The problem is that no scanners or puffers can detect PETN; only swabs and dogs work. What the TSA hopes is that they will detect the bulge if someone is hiding a wad of it on their person. But they won’t catch PETN hidden in a body cavity. That doesn’t have to be as gross as you’re imagining; you can hide PETN in your mouth. A terrorist can go through the scanners a dozen times with bits in his mouth each time, and assemble a bigger bomb on the other side. Or he can roll it thin enough to be part of a garment, and sneak it through that way. These tricks aren’t new. In the days after the Underwear Bomber was stopped, a scanner manufacturer admitted that the machines might not have caught him.

So what’s next? Strip searches? Body cavity searches? TSA Administrator John Pistole said there would be no body cavity searches for now, but his reasons make no sense. He said that the case widely reported as being a body cavity bomb might not actually have been. While that appears to be true, what does that have to do with future bombs? He also said that even body cavity bombs would need "external initiators" that the TSA would be able to detect.

Do you think for a minute that the TSA can detect these "external initiators"? Do you think that if a terrorist took a laptop — or better yet, a less-common piece of electronics gear — and removed the insides and replaced them with a timer, a pressure sensor, a simple contact switch, or a radio frequency switch, the TSA guy behind the X-ray machine monitor would detect it? How about if those components were distributed over a few trips through airport security. On the other hand, if we believe the TSA can magically detect these "external initiators" so effectively that they make body-cavity searches unnecessary, why do we need the full-body scanners?

Either PETN is a danger that must be searched for, or it isn’t. Pistole was being either ignorant or evasive.

Once again, the TSA is covering their own asses by implementing security-theater measures to prevent the previous attack while ignoring any threats of future attacks. It’s the same thinking that caused them to ban box cutters after 9/11, screen shoes after Richard Reid, limit liquids after that London gang, and — I kid you not — ban printer cartridges over 16 ounces after they were used to house package bombs from Yemen. They act like the terrorists are incapable of thinking creatively, while the terrorists repeatedly demonstrate that can always come up with a new approach that circumvents the old measures.

On the plus side, PETN is very hard to get to explode. The pre-9/11 screening procedures, looking for obvious guns and bombs, forced the terrorists to build inefficient fusing mechanisms. We saw this when Abdulmutallab, the Underwear Bomber, used bottles of liquid and a syringe and 20 minutes in the bathroom to assemble his device, then set his pants on fire — and still failed to ignite his PETN-filled underwear. And when he failed, the passengers quickly subdued him.

The truth is that exactly two things have made air travel safer since 9/11: reinforcing cockpit doors and convincing passengers they need to fight back. The TSA should continue to screen checked luggage. They should start screening airport workers. And then they should return airport security to pre-9/11 levels and let the rest of their budget be used for better purposes. Investigation and intelligence is how we’re going to prevent terrorism, on airplanes and elsewhere. It’s how we caught the liquid bombers. It’s how we found the Yemeni printer-cartridge bombs. And it’s our best chance at stopping the next serious plot.

Because if a group of well-planned and well-funded terrorist plotters makes it to the airport, the chance is pretty low that those blue-shirted crotch-groping water-bottle-confiscating TSA agents are going to catch them. The agents are trying to do a good job, but the deck is so stacked against them that their job is impossible. Airport security is the last line of defense, and it’s not a very good one.

We have a job here, too, and it’s to be indomitable in the face of terrorism. The goal of terrorism is to terrorize us: to make us afraid, and make our government do exactly what the TSA is doing. When we react out of fear, the terrorists succeed even when their plots fail. But if we carry on as before, the terrorists fail — even when their plots succeed.

This essay originally appeared on The Atlantic website.

Posted on December 3, 2010 at 6:20 AMView Comments

The Constitutionality of Full-Body Scanners

Jeffrey Rosen opines:

Although the Supreme Court hasn’t evaluated airport screening technology, lower courts have emphasized, as the U.S. Court of Appeals for the 9th Circuit ruled in 2007, that “a particular airport security screening search is constitutionally reasonable provided that it ‘is no more extensive nor intensive than necessary, in the light of current technology, to detect the presence of weapons or explosives.'”

In a 2006 opinion for the U.S. Court of Appeals for the 3rd Circuit, then-Judge Samuel Alito stressed that screening procedures must be both “minimally intrusive” and “effective” – in other words, they must be “well-tailored to protect personal privacy,” and they must deliver on their promise of discovering serious threats. Alito upheld the practices at an airport checkpoint where passengers were first screened with walk-through magnetometers and then, if they set off an alarm, with hand-held wands. He wrote that airport searches are reasonable if they escalate “in invasiveness only after a lower level of screening disclose[s] a reason to conduct a more probing search.”

As currently used in U.S. airports, the new full-body scanners fail all of Alito’s tests.

In other news, The New York Times wrote an editorial in favor of the scanners. I was surprised.

Posted on November 30, 2010 at 12:09 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.