Schneier on Security

Conversation with Kip Hawley, TSA Administrator (Part 1)

This is Part 1 of a five-part series. Link to whole thing.

In April, Kip Hawley, the head of the Transportation Security Administration (TSA), invited me to Washington for a meeting. Despite some serious trepidation, I accepted. And it was a good meeting. Most of it was off the record, but he asked me how the TSA could overcome its negative image. I told him to be more transparent, and stop ducking the hard questions. He said that he wanted to do that. He did enjoy writing a guest blog post for Aviation Daily, but having a blog himself didn’t work within the bureaucracy. What else could he do?

This interview, conducted in May and June via e-mail, was one of my suggestions.

Bruce Schneier: By today’s rules, I can carry on liquids in quantities of three ounces or less, unless they’re in larger bottles. But I can carry on multiple three-ounce bottles. Or a single larger bottle with a non-prescription medicine label, like contact lens fluid. It all has to fit inside a one-quart plastic bag, except for that large bottle of contact lens fluid. And if you confiscate my liquids, you’re going to toss them into a large pile right next to the screening station—which you would never do if anyone thought they were actually dangerous.

Can you please convince me there’s not an Office for Annoying Air Travelers making this sort of stuff up?

Kip Hawley: Screening ideas are indeed thought up by the Office for Annoying Air Travelers and vetted through the Directorate for Confusion and Complexity, and then we review them to insure that there are sufficient unintended irritating consequences so that the blogosphere is constantly fueled. Imagine for a moment that TSA people are somewhat bright, and motivated to protect the public with the least intrusion into their lives, not to mention travel themselves. How might you engineer backwards from that premise to get to three ounces and a baggie?

We faced a different kind of liquid explosive, one that was engineered to evade then-existing technology and process. Not the old Bojinka formula or other well-understood ones—TSA already trains and tests on those. After August 10, we began testing different variants with the national labs, among others, and engaged with other countries that have sophisticated explosives capabilities to find out what is necessary to reliably bring down a plane.

We started with the premise that we should prohibit only what’s needed from a security perspective. Otherwise, we would have stuck with a total liquid ban. But we learned through testing that that no matter what someone brought on, if it was in a small enough container, it wasn’t a serious threat. So what would the justification be for prohibiting lip gloss, nasal spray, etc? There was none, other than for our own convenience and the sake of a simple explanation.

Based on the scientific findings and a don’t-intrude-unless-needed-for-security philosophy, we came up with a container size that eliminates an assembled bomb (without having to determine what exactly is inside the bottle labeled “shampoo”), limits the total liquid any one person can bring (without requiring Transportation Security Officers (TSOs) to count individual bottles), and allows for additional security measures relating to multiple people mixing a bomb post-checkpoint. Three ounces and a baggie in the bin gives us a way for people to safely bring on limited quantities of liquids, aerosols and gels.

BS: How will this foil a plot, given that there are no consequences to trying? Airplane contraband falls into two broad categories: stuff you get in trouble for trying to smuggle onboard, and stuff that just gets taken away from you. If I’m caught at a security checkpoint with a gun or a bomb, you’re going to call the police and really ruin my day. But if I have a large bottle of that liquid explosive, you confiscate it with a smile and let me though. So unless you’re 100% perfect in catching this stuff—which you’re not—I can just try again and again until I get it through.

This isn’t like contaminants in food, where if you remove 90% of the particles, you’re 90% safer. None of those false alarms—none of those innocuous liquids taken away from innocent travelers—improve security. We’re only safer if you catch the one explosive liquid amongst the millions of containers of water, shampoo, and toothpaste. I have described two ways to get large amounts of liquids onto airplanes—large bottles labeled “saline solution” and trying until the screeners miss the liquid—not to mention combining multiple little bottles of liquid into one big bottle after the security checkpoint.

I want to assume the TSA is both intelligent and motivated to protect us. I’m taking your word for it that there is an actual threat—lots of chemists disagree—but your liquid ban isn’t mitigating it. Instead, I have the sinking feeling that you’re defending us against a terrorist smart enough to develop his own liquid explosive, yet too stupid to read the rules on TSA’s own website.

KH: I think your premise is wrong. There are consequences to coming to an airport with a bomb and having some of the materials taken away at the checkpoint. Putting aside our layers of security for the moment, there are things you can do to get a TSO’s attention at the checkpoint. If a TSO finds you or the contents of your bag suspicious, you might get interviewed and/or have your bags more closely examined. If the TSO throws your liquids in the trash, they don’t find you a threat.

I often read blog posts about how someone could just take all their three-ounce bottles—or take bottles from others on the plane—and combine them into a larger container to make a bomb. I can’t get into the specifics, but our explosives research shows this is not a viable option.

The current system is not the best we’ll ever come up with. In the near future, we’ll come up with an automated system to take care of liquids, and everyone will be happier.

In the meantime, we have begun using hand-held devices that can recognize threat liquids through factory-sealed containers (we will increase their number through the rest of the year) and we have different test strips that are effective when a bottle is opened. Right now, we’re using them on exempt items like medicines, as well as undeclared liquids TSOs find in bags. This will help close the vulnerability and strengthen the deterrent.

BS: People regularly point to security checkpoints missing a knife in their handbag as evidence that security screening isn’t working. But that’s wrong. Complete effectiveness is not the goal; the checkpoints just have to be effective enough so that the terrorists are worried their plan will be uncovered. But in Denver earlier this year, testers sneaked 90% of weapons through. And other tests aren’t much better. Why are these numbers so poor, and why didn’t they get better when the TSA took over airport security?

KH: Your first point is dead on and is the key to how we look at security. The stories about 90% failures are wrong or extremely misleading. We do many kinds of effectiveness tests at checkpoints daily. We use them to guide training and decisions on technology and operating procedures. We also do extensive and very sophisticated Red Team testing, and one of their jobs is to observe checkpoints and go back and figure out—based on inside knowledge of what we do—ways to beat the system. They isolate one particular thing: for example, a particular explosive, made and placed in a way that exploits a particular weakness in technology; our procedures; or the way TSOs do things in practice. Then they will test that particular thing over and over until they identify what corrective action is needed. We then change technology or procedure, or plain old focus on execution. And we repeat the process—forever.

So without getting into specifics on the test results, of course there are times that our evaluations can generate high failure rate numbers on specific scenarios. Overall, though, our ability to detect bomb components is vastly improved and it will keep getting better. (Older scores you may have seen may be “feel good” numbers based on old, easy tests. Don’t go for the sound-bite; today’s TSOs are light-years ahead of even where they were two years ago.)

Part 2: When can we keep our shoes on?

Tags: air travel, behavioral detection, bombs, DHS, homeland security, searches, security theater, sensors, trust, TSA, weapons

Posted on July 30, 2007 at 6:12 AM • 183 Comments