Entries Tagged "searches"

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Laptop Security while Crossing Borders

Last year, I wrote about the increasing propensity for governments, including the U.S. and Great Britain, to search the contents of people’s laptops at customs. What we know is still based on anecdote, as no country has clarified the rules about what their customs officers are and are not allowed to do, and what rights people have.

Companies and individuals have dealt with this problem in several ways, from keeping sensitive data off laptops traveling internationally, to storing the data—encrypted, of course—on websites and then downloading it at the destination. I have never liked either solution. I do a lot of work on the road, and need to carry all sorts of data with me all the time. It’s a lot of data, and downloading it can take a long time. Also, I like to work on long international flights.

There’s another solution, one that works with whole-disk encryption products like PGP Disk (I’m on PGP’s advisory board), TrueCrypt, and BitLocker: Encrypt the data to a key you don’t know.

It sounds crazy, but stay with me. Caveat: Don’t try this at home if you’re not very familiar with whatever encryption product you’re using. Failure results in a bricked computer. Don’t blame me.

Step One: Before you board your plane, add another key to your whole-disk encryption (it’ll probably mean adding another “user”)—and make it random. By “random,” I mean really random: Pound the keyboard for a while, like a monkey trying to write Shakespeare. Don’t make it memorable. Don’t even try to memorize it.

Technically, this key doesn’t directly encrypt your hard drive. Instead, it encrypts the key that is used to encrypt your hard drive—that’s how the software allows multiple users.

So now there are two different users named with two different keys: the one you normally use, and some random one you just invented.

Step Two: Send that new random key to someone you trust. Make sure the trusted recipient has it, and make sure it works. You won’t be able to recover your hard drive without it.

Step Three: Burn, shred, delete or otherwise destroy all copies of that new random key. Forget it. If it was sufficiently random and non-memorable, this should be easy.

Step Four: Board your plane normally and use your computer for the whole flight.

Step Five: Before you land, delete the key you normally use.

At this point, you will not be able to boot your computer. The only key remaining is the one you forgot in Step Three. There’s no need to lie to the customs official; you can even show him a copy of this article if he doesn’t believe you.

Step Six: When you’re safely through customs, get that random key back from your confidant, boot your computer and re-add the key you normally use to access your hard drive.

And that’s it.

This is by no means a magic get-through-customs-easily card. Your computer might be impounded, and you might be taken to court and compelled to reveal who has the random key.

But the purpose of this protocol isn’t to prevent all that; it’s just to deny any possible access to your computer to customs. You might be delayed. You might have your computer seized. (This will cost you any work you did on the flight, but—honestly—at that point that’s the least of your troubles.) You might be turned back or sent home. But when you’re back home, you have access to your corporate management, your personal attorneys, your wits after a good night’s sleep, and all the rights you normally have in whatever country you’re now in.

This procedure not only protects you against the warrantless search of your data at the border, it also allows you to deny a customs official your data without having to lie or pretend—which itself is often a crime.

Now the big question: Who should you send that random key to?

Certainly it should be someone you trust, but—more importantly—it should be someone with whom you have a privileged relationship. Depending on the laws in your country, this could be your spouse, your attorney, your business partner or your priest. In a larger company, the IT department could institutionalize this as a policy, with the help desk acting as the key holder.

You could also send it to yourself, but be careful. You don’t want to e-mail it to your webmail account, because then you’d be lying when you tell the customs official that there is no possible way you can decrypt the drive.

You could put the key on a USB drive and send it to your destination, but there are potential failure modes. It could fail to get there in time to be waiting for your arrival, or it might not get there at all. You could airmail the drive with the key on it to yourself a couple of times, in a couple of different ways, and also fax the key to yourself … but that’s more work than I want to do when I’m traveling.

If you only care about the return trip, you can set it up before you return. Or you can set up an elaborate one-time pad system, with identical lists of keys with you and at home: Destroy each key on the list you have with you as you use it.

Remember that you’ll need to have full-disk encryption, using a product such as PGP Disk, TrueCrypt or BitLocker, already installed and enabled to make this work.

I don’t think we’ll ever get to the point where our computer data is safe when crossing an international border. Even if countries like the U.S. and Britain clarify their rules and institute privacy protections, there will always be other countries that will exercise greater latitude with their authority. And sometimes protecting your data means protecting your data from yourself.

This essay originally appeared on Wired.com.

Posted on July 15, 2009 at 12:10 PM • View Comments

Court Limits on TSA Searches

This is good news:

A federal judge in June threw out seizure of three fake passports from a traveler, saying that TSA screeners violated his Fourth Amendment rights against unreasonable search and seizure. Congress authorizes TSA to search travelers for weapons and explosives; beyond that, the agency is overstepping its bounds, U.S. District Court Judge Algenon L. Marbley said.

“The extent of the search went beyond the permissible purpose of detecting weapons and explosives and was instead motivated by a desire to uncover contraband evidencing ordinary criminal wrongdoing,” Judge Marbley wrote.

In the second case, Steven Bierfeldt, treasurer for the Campaign for Liberty, a political organization launched from Ron Paul’s presidential run, was detained at the St. Louis airport because he was carrying $4,700 in a lock box from the sale of tickets, T-shirts, bumper stickers and campaign paraphernalia. TSA screeners quizzed him about the cash, his employment and the purpose of his trip to St. Louis, then summoned local police and threatened him with arrest because he responded to their questions with a question of his own: What were his rights and could TSA legally require him to answer?

[…]

Mr. Bierfeldt’s suit, filed in U.S. District Court in the District of Columbia, seeks to bar TSA from “conducting suspicion-less pre-flight searches of passengers or their belongings for items other than weapons or explosives.”

I wrote about this a couple of weeks ago:

…Obama should mandate that airport security be solely about terrorism, and not a general-purpose security checkpoint to catch everyone from pot smokers to deadbeat dads.

The Constitution provides us, both Americans and visitors to America, with strong protections against invasive police searches. Two exceptions come into play at airport security checkpoints. The first is “implied consent,” which means that you cannot refuse to be searched; your consent is implied when you purchased your ticket. And the second is “plain view,” which means that if the TSA officer happens to see something unrelated to airport security while screening you, he is allowed to act on that.

Both of these principles are well established and make sense, but it’s their combination that turns airport security checkpoints into police-state-like checkpoints.

The TSA should limit its searches to bombs and weapons and leave general policing to the police—where we know courts and the Constitution still apply.

Posted on July 8, 2009 at 6:42 AM • View Comments

Update on Computer Science Student's Computer Seizure

In April, I blogged about the Boston police seizing a student’s computer for, among other things, running Linux. (Anyone who runs Linux instead of Windows is obviously a scary bad hacker.)

Last week, the Massachusetts Supreme Court threw out the search warrant:

Massachusetts Supreme Judicial Court Associate Justice Margot Botsford on Thursday said that Boston College and Massachusetts State Police had insufficient evidence to search the dorm room of BC senior Riccardo Calixte. During the search, police confiscated a variety of electronic devices, including three laptop computers, two iPod music players, and two cellphones.

Police obtained a warrant to search Calixte’s dorm after a roommate accused him of breaking into the school’s computer network to change other students’ grades, and of spreading a rumor via e-mail that the roommate is gay.

Botsford said the search warrant affidavit presented considerable evidence that the e-mail came from Calixte’s laptop computer. But even if it did, she said, spreading such rumors is probably not illegal. Botsford also said that while breaking into BC’s computer network would be criminal activity, the affidavit supporting the warrant presented little evidence that such a break-in had taken place.

Posted on June 2, 2009 at 12:01 PM • View Comments

Me on Full-Body Scanners in Airports

I’m very happy with this quote in a CNN.com story on “whole-body imaging” at airports:

Bruce Schneier, an internationally recognized security technologist, said whole-body imaging technology “works pretty well,” privacy rights aside. But he thinks the financial investment was a mistake. In a post-9/11 world, he said, he knows his position isn’t “politically tenable,” but he believes money would be better spent on intelligence-gathering and investigations.

“It’s stupid to spend money so terrorists can change plans,” he said by phone from Poland, where he was speaking at a conference. If terrorists are swayed from going through airports, they’ll just target other locations, such as a hotel in Mumbai, India, he said.

“We’d be much better off going after bad guys … and back to pre-9/11 levels of airport security,” he said. “There’s a huge ‘cover your ass’ factor in politics, but unfortunately, it doesn’t make us safer.”

I’ve written about “cover your ass” security in the past, but it’s nice to see it in the press.

Posted on May 20, 2009 at 2:34 PM • View Comments

No Warrant Required for GPS Tracking

At least, according to a Wisconsin appeals court ruling:

As the law currently stands, the court said police can mount GPS on cars to track people without violating their constitutional rights—even if the drivers aren’t suspects.

Officers do not need to get warrants beforehand because GPS tracking does not involve a search or a seizure, Judge Paul Lundsten wrote for the unanimous three-judge panel based in Madison.

That means “police are seemingly free to secretly track anyone’s public movements with a GPS device,” he wrote.

The court wants the legislature to fix it:

However, the District 4 Court of Appeals said it was “more than a little troubled” by that conclusion and asked Wisconsin lawmakers to regulate GPS use to protect against abuse by police and private individuals.

I think the odds of that happening are approximately zero.

Posted on May 15, 2009 at 6:30 AM • View Comments

Software Problems with a Breath Alcohol Detector

This is an excellent lesson in the security problems inherent in trusting proprietary software:

After two years of attempting to get the computer based source code for the Alcotest 7110 MKIII-C, defense counsel in State v. Chun were successful in obtaining the code, and had it analyzed by Base One Technologies, Inc.

Draeger, the manufacturer maintained that the system was perfect, and that revealing the source code would be damaging to its business. They were right about the second part, of course, because it turned out that the code was terrible.

2. Readings are Not Averaged Correctly: When the software takes a series of readings, it first averages the first two readings. Then, it averages the third reading with the average just computed. Then the fourth reading is averaged with the new average, and so on. There is no comment or note detailing a reason for this calculation, which would cause the first reading to have more weight than successive readings. Nonetheless, the comments say that the values should be averaged, and they are not.

3. Results Limited to Small, Discrete Values: The A/D converters measuring the IR readings and the fuel cell readings can produce values between 0 and 4095. However, the software divides the final average(s) by 256, meaning the final result can only have 16 values to represent the five-volt range (or less), or, represent the range of alcohol readings possible. This is a loss of precision in the data; of a possible twelve bits of information, only four bits are used. Further, because of an attribute in the IR calculations, the result value is further divided in half. This means that only 8 values are possible for the IR detection, and this is compared against the 16 values of the fuel cell.

4. Catastrophic Error Detection Is Disabled: An interrupt that detects that the microprocessor is trying to execute an illegal instruction is disabled, meaning that the Alcotest software could appear to run correctly while executing wild branches or invalid code for a period of time. Other interrupts ignored are the Computer Operating Property (a watchdog timer), and the Software Interrupt.

Basically, the system was designed to return some sort of result regardless.

This is important. As we become more and more dependent on software for evidentiary and other legal applications, we need to be able to carefully examine that software for accuracy, reliability, etc. Every government contract for breath alcohol detectors needs to include the requirement for public source code. “You can’t look at our code because we don’t want you to” simply isn’t good enough.

Posted on May 13, 2009 at 2:07 PM • View Comments

Privacy in Google Latitude

Good news:

What Loopt—and now Google—are asserting is this: when you tell your friends where you are, you are using a public conveyance to communicate privately. And, just as it would if it wanted to record your phone call or read your e-mail, the government needs to get a wiretap order. That’s even tougher to get than a search warrant.

Posted on March 16, 2009 at 6:36 AM • View Comments

The Exclusionary Rule and Security

Earlier this month, the Supreme Court ruled that evidence gathered as a result of errors in a police database is admissible in court. Their narrow decision is wrong, and will only ensure that police databases remain error-filled in the future.

The specifics of the case are simple. A computer database said there was a felony arrest warrant pending for Bennie Herring when there actually wasn’t. When the police came to arrest him, they searched his home and found illegal drugs and a gun. The Supreme Court was asked to rule whether the police had the right to arrest him for possessing those items, even though there was no legal basis for the search and arrest in the first place.

What’s at issue here is the exclusionary rule, which basically says that unconstitutionally or illegally collected evidence is inadmissible in court. It might seem like a technicality, but excluding what is called “the fruit of the poisonous tree” is a security system designed to protect us all from police abuse.

We have a number of rules limiting what the police can do: rules governing arrest, search, interrogation, detention, prosecution, and so on. And one of the ways we ensure that the police follow these rules is by forbidding the police to receive any benefit from breaking them. In fact, we design the system so that the police actually harm their own interests by breaking them, because all evidence that stems from breaking the rules is inadmissible.

And that’s what the exclusionary rule does. If the police search your home without a warrant and find drugs, they can’t arrest you for possession. Since the police have better things to do than waste their time, they have an incentive to get a warrant.

The Herring case is more complicated, because the police thought they did have a warrant. The error was not a police error, but a database error. And, in fact, Judge Roberts wrote for the majority: “The exclusionary rule serves to deter deliberate, reckless, or grossly negligent conduct, or in some circumstances recurring or systemic negligence. The error in this case does not rise to that level.”

Unfortunately, Roberts is wrong. Government databases are filled with errors. People often can’t see data about themselves, and have no way to correct the errors if they do learn of any. And more and more databases are trying to exempt themselves from the Privacy Act of 1974, and specifically the provisions that require data accuracy. The legal argument for excluding this evidence was best made by an amicus curiae brief filed by the Electronic Privacy Information Center, but in short, the court should exclude the evidence because it’s the only way to ensure police database accuracy.

We are protected from becoming a police state by limits on police power and authority. This is not a trade-off we make lightly: we deliberately hamper law enforcement’s ability to do its job because we recognize that these limits make us safer. Without the exclusionary rule, your only remedy against an illegal search is to bring legal action against the police—and that can be very difficult. We, the people, would rather have you go free than motivate the police to ignore the rules that limit their power.

By not applying the exclusionary rule in the Herring case, the Supreme Court missed an important opportunity to motivate the police to purge errors from their databases. Constitutional lawyers have written many articles about this ruling, but the most interesting idea comes from George Washington University professor Daniel J. Solove, who proposes this compromise: “If a particular database has reasonable protections and deterrents against errors, then the Fourth Amendment exclusionary rule should not apply. If not, then the exclusionary rule should apply. Such a rule would create an incentive for law enforcement officials to maintain accurate databases, to avoid all errors, and would ensure that there would be a penalty or consequence for errors.”

Increasingly, we are being judged by the trail of data we leave behind us. Increasingly, data accuracy is vital to our personal safety and security. And if errors made by police databases aren’t held to the same legal standard as errors made by policemen, then more and more innocent Americans will find themselves the victims of incorrect data.

This essay originally appeared on the Wall Street Journal website.

EDITED TO ADD (2/1): More on the assault on the exclusionary rule.

EDITED TO ADD (2/9): Here’s another recent court case involving the exclusionary rule, and a thoughtful analysis by Orin Kerr.

Posted on January 28, 2009 at 7:12 AM • View Comments

Bypassing Airport Checkpoints

From a reader:

I always get a giggle from reading about TSA security procedures, because of what I go through during my occasional job at an airport. I repair commercial kitchen cooking equipment—restaurants etc. On occasion I have to go to restaurants inside a nearby airport terminal to repair equipment, sometimes needing a return trip with parts.

So here’s the scene. I park inside the parking garage area in my company truck. I carry my 30 pound toolbox and a large cardboard box, about 2 1/2 feet long with parts for a broiler to be repaired. I go to a restaurant outside the security zone and pick up an “escort”, typically a kid of maybe 25 years old. I obviously can’t go through the TSA checkpoint, as they’d have absolute conniptions about my tools and large parts. So, without ever having to show ID, or even looking at what I may have in the large cardboard box or my large metal toolbox, the escort takes me down an elevator, out onto the tarmac, past waiting planes pulled up to the terminal, back inside the terminal building and coming out on the other side of the TSA checkpoint, then off to the restaurant to be repaired. Then, when I’m done, they escort my out the normal way, past the TSA screening area, with my toolbox and large cardboard box in hand. No one bats an eye as to what might have transpired or how my stuff magically appeared on the “secure” side and is now leaving right in front of them

And people wonder why I call it all security theater?

Posted on December 18, 2008 at 10:19 AM • View Comments

Ed Felten on TSA Behavioral Screening

Good comment:

Now suppose that TSA head Kip Hawley came to you and asked you to submit voluntarily to a pat-down search the next time you travel. And suppose you knew, with complete certainty, that if you agreed to the search, this would magically give the TSA a 0.1% chance of stopping a deadly crime. You’d agree to the search, wouldn’t you? Any reasonable person would accept the search to save (by assumption) at least 0.001 lives. This hypothetical TSA program is reasonable, even though it only has a 0.1% arrest rate. (I’m assuming here that an attack would cost only one life. Attacks that killed more people would justify searches with an even smaller arrest rate.)

So the commentators’ critique is weak—but of course this doesn’t mean the TSA program should be seen as a success. The article says that the arrests the system generates are mostly for drug charges or carrying a false ID. Should a false-ID arrest be considered a success for the system? Certainly we don’t want to condone the use of false ID, but I’d bet most of these people are just trying to save money by flying on a ticket in another person’s name—which hardly makes them Public Enemy Number One. Is it really worth doing hundreds of searches to catch one such person? Are those searches really the best use of TSA screeners’ time? Probably not.

Right. It’s not just about the hit rate. It’s the cost vs. benefit: cost in taxpayer money, passenger time, TSA screener attention, fundamental liberties, etc.

Posted on December 17, 2008 at 6:38 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.