Entries Tagged "essays"

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The Legacy of DES

The Data Encryption Standard, or DES, was a mid-’70s brainchild of the National Bureau of Standards: the first modern, public, freely available encryption algorithm. For over two decades, DES was the workhorse of commercial cryptography.

Over the decades, DES has been used to protect everything from databases in mainframe computers, to the communications links between ATMs and banks, to data transmissions between police cars and police stations. Whoever you are, I can guarantee that many times in your life, the security of your data was protected by DES.

Just last month, the former National Bureau of Standards—the agency is now called the National Institute of Standards and Technology, or NIST—proposed withdrawing DES as an encryption standard, signifying the end of the federal government’s most important technology standard, one more important than ASCII, I would argue.

Today, cryptography is one of the most basic tools of computer security, but 30 years ago it barely existed as an academic discipline. In the days when the Internet was little more than a curiosity, cryptography wasn’t even a recognized branch of mathematics. Secret codes were always fascinating, but they were pencil-and-paper codes based on alphabets. In the secret government labs during World War II, cryptography entered the computer era and became mathematics. But with no professors teaching it, and no conferences discussing it, all the cryptographic research in the United States was conducted at the National Security Agency.

And then came DES.

Back in the early 1970s, it was a radical idea. The National Bureau of Standards decided that there should be a free encryption standard. Because the agency wanted it to be non-military, they solicited encryption algorithms from the public. They got only one serious response—the Data Encryption Standard—from the labs of IBM. In 1976, DES became the government’s standard encryption algorithm for “sensitive but unclassified” traffic. This included things like personal, financial and logistical information. And simply because there was nothing else, companies began using DES whenever they needed an encryption algorithm. Of course, not everyone believed DES was secure.

When IBM submitted DES as a standard, no one outside the National Security Agency had any expertise to analyze it. The NSA made two changes to DES: It tweaked the algorithm, and it cut the key size by more than half.

The strength of an algorithm is based on two things: how good the mathematics is, and how long the key is. A sure way of breaking an algorithm is to try every possible key. Modern algorithms have a key so long that this is impossible; even if you built a computer out of all the silicon atoms on the planet and ran it for millions of years, you couldn’t do it. So cryptographers look for shortcuts. If the mathematics are weak, maybe there’s a way to find the key faster: “breaking” the algorithm.

The NSA’s changes caused outcry among the few who paid attention, both regarding the “invisible hand” of the NSA—the tweaks were not made public, and no rationale was given for the final design—and the short key length.

But with the outcry came research. It’s not an exaggeration to say that the publication of DES created the modern academic discipline of cryptography. The first academic cryptographers began their careers by trying to break DES, or at least trying to understand the NSA’s tweak. And almost all of the encryption algorithms—public-key cryptography, in particular—can trace their roots back to DES. Papers analyzing different aspects of DES are still being published today.

By the mid-1990s, it became widely believed that the NSA was able to break DES by trying every possible key. This ability was demonstrated in 1998, when a $220,000 machine was built that could brute-force a DES key in a few days. In 1985, the academic community proposed a DES variant with the same mathematics but a longer key, called triple-DES. This variant had been used in more secure applications in place of DES for years, but it was time for a new standard. In 1997, NIST solicited an algorithm to replace DES.

The process illustrates the complete transformation of cryptography from a secretive NSA technology to a worldwide public technology. NIST once again solicited algorithms from the public, but this time the agency got 15 submissions from 10 countries. My own algorithm, Twofish, was one of them. And after two years of analysis and debate, NIST chose a Belgian algorithm, Rijndael, to become the Advanced Encryption Standard.

It’s a different world in cryptography now than it was 30 years ago. We know more about cryptography, and have more algorithms to choose among. AES won’t become a ubiquitous standard in the same way that DES did. But it is finding its way into banking security products, Internet security protocols, even computerized voting machines. A NIST standard is an imprimatur of quality and security, and vendors recognize that.

So, how good is the NSA at cryptography? They’re certainly better than the academic world. They have more mathematicians working on the problems, they’ve been working on them longer, and they have access to everything published in the academic world, while they don’t have to make their own results public. But are they a year ahead of the state of the art? Five years? A decade? No one knows.

It took the academic community two decades to figure out that the NSA “tweaks” actually improved the security of DES. This means that back in the ’70s, the National Security Agency was two decades ahead of the state of the art.

Today, the NSA is still smarter, but the rest of us are catching up quickly. In 1999, the academic community discovered a weakness in another NSA algorithm, SHA, that the NSA claimed to have discovered only four years previously. And just last week there was a published analysis of the NSA’s SHA-1 that demonstrated weaknesses that we believe the NSA didn’t know about at all.

Maybe now we’re just a couple of years behind.

This essay was originally published on CNet.com

Posted on October 6, 2004 at 6:05 PMView Comments

RFID Passports

Since the terrorist attacks of 2001, the Bush administration—specifically, the Department of Homeland Security—has wanted the world to agree on a standard for machine-readable passports. Countries whose citizens currently do not have visa requirements to enter the United States will have to issue passports that conform to the standard or risk losing their nonvisa status.

These future passports, currently being tested, will include an embedded computer chip. This chip will allow the passport to contain much more information than a simple machine-readable character font, and will allow passport officials to quickly and easily read that information. That is a reasonable requirement and a good idea for bringing passport technology into the 21st century.

But the Bush administration is advocating radio frequency identification (RFID) chips for both U.S. and foreign passports, and that’s a very bad thing.

These chips are like smart cards, but they can be read from a distance. A receiving device can “talk” to the chip remotely, without any need for physical contact, and get whatever information is on it. Passport officials envision being able to download the information on the chip simply by bringing it within a few centimeters of an electronic reader.

Unfortunately, RFID chips can be read by any reader, not just the ones at passport control. The upshot of this is that travelers carrying around RFID passports are broadcasting their identity.

Think about what that means for a minute. It means that passport holders are continuously broadcasting their name, nationality, age, address and whatever else is on the RFID chip. It means that anyone with a reader can learn that information, without the passport holder’s knowledge or consent. It means that pickpockets, kidnappers and terrorists can easily—and surreptitiously—pick Americans or nationals of other participating countries out of a crowd.

It is a clear threat to both privacy and personal safety, and quite simply, that is why it is bad idea. Proponents of the system claim that the chips can be read only from within a distance of a few centimeters, so there is no potential for abuse. This is a spectacularly naïve claim. All wireless protocols can work at much longer ranges than specified. In tests, RFID chips have been read by receivers 20 meters away. Improvements in technology are inevitable.

Security is always a trade-off. If the benefits of RFID outweighed the risks, then maybe it would be worth it. Certainly, there isn’t a significant benefit when people present their passport to a customs official. If that customs official is going to take the passport and bring it near a reader, why can’t he go those extra few centimeters that a contact chip—one the reader must actually touch—would require?

The Bush administration is deliberately choosing a less secure technology without justification. If there were a good offsetting reason to choose that technology over a contact chip, then the choice might make sense.

Unfortunately, there is only one possible reason: The administration wants surreptitious access themselves. It wants to be able to identify people in crowds. It wants to surreptitiously pick out the Americans, and pick out the foreigners. It wants to do the very thing that it insists, despite demonstrations to the contrary, can’t be done.

Normally I am very careful before I ascribe such sinister motives to a government agency. Incompetence is the norm, and malevolence is much rarer. But this seems like a clear case of the Bush administration putting its own interests above the security and privacy of its citizens, and then lying about it.

This article originally appeared in the 4 October 2004 edition of the International Herald Tribune.

Posted on October 4, 2004 at 7:20 PMView Comments

Aerial Surveillance to Detect Building Code Violations

The Baltimore housing department has a new tool to find homeowners who have been building rooftop decks without a permit: aerial mapping. Baltimore bought aerial photographs of the entire city and used software to correlate the images with databases of address information and permit records. Inspectors have just begun knocking on doors of residents who built decks without permission.

On the face of it, this is nothing new. Police always have been able to inspect buildings for permit violations. The difference is they would do it manually, and that limited its use. It simply wasn’t feasible for the police to automatically document every building code violation in any city. What’s different isn’t the police tactic but the efficiency of the process.

Technology is fundamentally changing the nature of surveillance. Years ago, surveillance involved trench-coated detectives following people down streets. It was laborious and expensive, and was only used when there was reasonable suspicion of a crime. Modern surveillance is the police officer sitting at a computer with a satellite image of an entire neighborhood. It’s the same, but it’s completely different. It’s wholesale surveillance.

And it disrupts the balance between the powers of the police and the rights of the people.

Wholesale surveillance is fast becoming the norm. Security cameras are everywhere, even in places satellites can’t see. Automatic toll road devices track cars at tunnels and bridges. We can all be tracked by our cell phones. Our purchases are tracked by banks and credit card companies, our telephone calls by phone companies, our Internet surfing habits by Web site operators.

Like the satellite images, the electronic footprints we leave everywhere can be automatically correlated with databases. The data can be stored forever, allowing police to conduct surveillance backward in time.

The effects of wholesale surveillance on privacy and civil liberties is profound, but unfortunately, the debate often gets mischaracterized as a question about how much privacy we need to give up in order to be secure. This is wrong. It’s obvious that we are all safer when the police can use all possible crimefighting techniques. The Fourth Amendment already allows police to perform even the most intrusive searches of your home and person.

What we need are mechanisms to prevent abuse and hold the police accountable and assurances that the new techniques don’t place an unreasonable burden on the innocent. In many cases, the Fourth Amendment already provides for this in its requirement of a warrant.

The warrant process requires that a “neutral and detached magistrate” review the basis for the search and take responsibility for the outcome. The key is independent judicial oversight; the warrant process is itself a security measure that protects us from abuse and makes us more secure.

This works for some searches, but not for most wholesale surveillance. The courts already have ruled that the police cannot use thermal imaging to see through the walls of your home without a warrant, but that it’s OK for them to fly overhead and peer over your fences without a warrant. They need a warrant before opening your paper mail or listening in on your phone calls.

Wholesale surveillance calls for something else: lessening of criminal penalties. The reason criminal punishments are severe is to create a deterrent because it is hard to catch wrongdoers. As they become easier to catch, a realignment is necessary. When the police can automate the detection of a wrongdoing, perhaps there should no longer be any criminal penalty attached. For example, red-light cameras and speed-trap cameras issue citations without any “points” assessed against drivers.

Another obvious protection is notice. Baltimore should send mail to every homeowner announcing the use of aerial photography to document building code violations, urging individuals to come into compliance.

Wholesale surveillance is not simply a more efficient way for the police to do what they’ve always done. It’s a new police power, one made possible with today’s technology and one that will be made easier with tomorrow’s. And with any new police power, we as a society need to take an active role in establishing rules governing its use. To do otherwise is to cede ever more authority to the police.

This article was originally published in the 4 October 2004 edition of the Baltimore Sun.

Posted on October 4, 2004 at 7:18 PMView Comments

Aerial Surveillance to Detect Building Code Violations

The Baltimore housing department has a new tool to find homeowners who have been building rooftop decks without a permit: aerial mapping. Baltimore bought aerial photographs of the entire city and used software to correlate the images with databases of address information and permit records. Inspectors have just begun knocking on doors of residents who built decks without permission.

On the face of it, this is nothing new. Police always have been able to inspect buildings for permit violations. The difference is they would do it manually, and that limited its use. It simply wasn’t feasible for the police to automatically document every building code violation in any city. What’s different isn’t the police tactic but the efficiency of the process.

Technology is fundamentally changing the nature of surveillance. Years ago, surveillance involved trench-coated detectives following people down streets. It was laborious and expensive, and was only used when there was reasonable suspicion of a crime. Modern surveillance is the police officer sitting at a computer with a satellite image of an entire neighborhood. It’s the same, but it’s completely different. It’s wholesale surveillance.

And it disrupts the balance between the powers of the police and the rights of the people.

Wholesale surveillance is fast becoming the norm. Security cameras are everywhere, even in places satellites can’t see. Automatic toll road devices track cars at tunnels and bridges. We can all be tracked by our cell phones. Our purchases are tracked by banks and credit card companies, our telephone calls by phone companies, our Internet surfing habits by Web site operators.

Like the satellite images, the electronic footprints we leave everywhere can be automatically correlated with databases. The data can be stored forever, allowing police to conduct surveillance backward in time.

The effects of wholesale surveillance on privacy and civil liberties is profound, but unfortunately, the debate often gets mischaracterized as a question about how much privacy we need to give up in order to be secure. This is wrong. It’s obvious that we are all safer when the police can use all possible crimefighting techniques. The Fourth Amendment already allows police to perform even the most intrusive searches of your home and person.

What we need are mechanisms to prevent abuse and hold the police accountable and assurances that the new techniques don’t place an unreasonable burden on the innocent. In many cases, the Fourth Amendment already provides for this in its requirement of a warrant.

The warrant process requires that a “neutral and detached magistrate” review the basis for the search and take responsibility for the outcome. The key is independent judicial oversight; the warrant process is itself a security measure that protects us from abuse and makes us more secure.

This works for some searches, but not for most wholesale surveillance. The courts already have ruled that the police cannot use thermal imaging to see through the walls of your home without a warrant, but that it’s OK for them to fly overhead and peer over your fences without a warrant. They need a warrant before opening your paper mail or listening in on your phone calls.

Wholesale surveillance calls for something else: lessening of criminal penalties. The reason criminal punishments are severe is to create a deterrent because it is hard to catch wrongdoers. As they become easier to catch, a realignment is necessary. When the police can automate the detection of a wrongdoing, perhaps there should no longer be any criminal penalty attached. For example, red-light cameras and speed-trap cameras issue citations without any “points” assessed against drivers.

Another obvious protection is notice. Baltimore should send mail to every homeowner announcing the use of aerial photography to document building code violations, urging individuals to come into compliance.

Wholesale surveillance is not simply a more efficient way for the police to do what they’ve always done. It’s a new police power, one made possible with today’s technology and one that will be made easier with tomorrow’s. And with any new police power, we as a society need to take an active role in establishing rules governing its use. To do otherwise is to cede ever more authority to the police.

This article was originally published in the 4 October 2004 edition of the Baltimore Sun.

Posted on October 4, 2004 at 7:18 PMView Comments

Do Terror Alerts Work?

As I read the litany of terror threat warnings that the government has issued in the past three years, the thing that jumps out at me is how vague they are. The careful wording implies everything without actually saying anything. We hear “terrorists might try to bomb buses and rail lines in major U.S. cities this summer,” and there’s “increasing concern about the possibility of a major terrorist attack.” “At least one of these attacks could be executed by the end of the summer 2003.” Warnings are based on “uncorroborated intelligence,” and issued even though “there is no credible, specific information about targets or method of attack.” And, of course, “weapons of mass destruction, including those containing chemical, biological, or radiological agents or materials, cannot be discounted.”

Terrorists might carry out their attacks using cropdusters, helicopters, scuba divers, even prescription drugs from Canada. They might be carrying almanacs. They might strike during the Christmas season, disrupt the “democratic process,” or target financial buildings in New York and Washington.

It’s been more than two years since the government instituted a color-coded terror alert system, and the Department of Homeland Security has issued about a dozen terror alerts in that time. How effective have they been in preventing terrorism? Have they made us any safer, or are they causing harm? Are they, as critics claim, just a political ploy?

When Attorney General John Ashcroft came to Minnesota recently, he said the fact that there had been no terrorist attacks in America in the three years since September 11th was proof that the Bush administration’s anti-terrorist policies were working. I thought: There were no terrorist attacks in America in the three years before September 11th, and we didn’t have any terror alerts. What does that prove?

In theory, the warnings are supposed to cultivate an atmosphere of preparedness. If Americans are vigilant against the terrorist threat, then maybe the terrorists will be caught and their plots foiled. And repeated warnings brace Americans for the aftermath of another attack.

The problem is that the warnings don’t do any of this. Because they are so vague and so frequent, and because they don’t recommend any useful actions that people can take, terror threat warnings don’t prevent terrorist attacks. They might force a terrorist to delay his plan temporarily, or change his target. But in general, professional security experts like me are not particularly impressed by systems that merely force the bad guys to make minor modifications in their tactics.

And the alerts don’t result in a more vigilant America. It’s one thing to issue a hurricane warning, and advise people to board up their windows and remain in the basement. Hurricanes are short-term events, and it’s obvious when the danger is imminent and when it’s over. People can do useful things in response to a hurricane warning; then there is a discrete period when their lives are markedly different, and they feel there was utility in the higher alert mode, even if nothing came of it.

It’s quite another thing to tell people to be on alert, but not to alter their plans—as Americans were instructed last Christmas. A terrorist alert that instills a vague feeling of dread or panic, without giving people anything to do in response, is ineffective. Indeed, it inspires terror itself. Compare people’s reactions to hurricane threats with their reactions to earthquake threats. According to scientists, California is expecting a huge earthquake sometime in the next two hundred years. Even though the magnitude of the disaster will be enormous, people just can’t stay alert for two centuries. The news seems to have generated the same levels of short-term fear and long-term apathy in Californians that the terrorist warnings do. It’s human nature; people simply can’t be vigilant indefinitely.

It’s true too that people want to make their own decisions. Regardless of what the government suggests, people are going to independently assess the situation. They’re going to decide for themselves whether or not changing their behavior seems like a good idea. If there’s no rational information to base their independent assessment on, they’re going to come to conclusions based on fear, prejudice, or ignorance.

We’re already seeing this in the U.S. We see it when Muslim men are assaulted on the street. We see it when a woman on an airplane panics because a Syrian pop group is flying with her. We see it again and again, as people react to rumors about terrorist threats from Al Qaeda and its allies endlessly repeated by the news media.

This all implies that if the government is going to issue a threat warning at all, it should provide as many details as possible. But this is a catch-22: Unfortunately, there’s an absolute limit to how much information the government can reveal. The classified nature of the intelligence that goes into these threat alerts precludes the government from giving the public all the information it would need to be meaningfully prepared. And maddeningly, the current administration occasionally compromises the intelligence assets it does have, in the interest of politics. It recently released the name of a Pakistani agent working undercover in Al Qaeda, blowing ongoing counterterrorist operations both in Pakistan and the U.K.

Still, ironically, most of the time the administration projects a “just trust me” attitude. And there are those in the U.S. who trust it, and there are those who do not. Unfortunately, there are good reasons not to trust it. There are two reasons government likes terror alerts. Both are self-serving, and neither has anything to do with security.

The first is such a common impulse of bureaucratic self-protection that it has achieved a popular acronym in government circles: CYA. If the worst happens and another attack occurs, the American public isn’t going to be as sympathetic to the current administration as it was last time. After the September 11th attacks, the public reaction was primarily shock and disbelief. In response, the government vowed to fight the terrorists. They passed the draconian USA PATRIOT Act, invaded two countries, and spent hundreds of billions of dollars. Next time, the public reaction will quickly turn into anger, and those in charge will need to explain why they failed. The public is going to demand to know what the government knew and why it didn’t warn people, and they’re not going to look kindly on someone who says: “We didn’t think the threat was serious enough to warn people.” Issuing threat warnings is a way to cover themselves. “What did you expect?” they’ll say. “We told you it was Code Orange.”

The second purpose is even more self-serving: Terror threat warnings are a publicity tool. They’re a method of keeping terrorism in people’s minds. Terrorist attacks on American soil are rare, and unless the topic stays in the news, people will move on to other concerns. There is, of course, a hierarchy to these things. Threats against U.S. soil are most important, threats against Americans abroad are next, and terrorist threats—even actual terrorist attacks—against foreigners in foreign countries are largely ignored.

Since the September 11th attacks, Republicans have made “tough on terror” the centerpiece of their reelection strategies. Study after study has shown that Americans who are worried about terrorism are more likely to vote Republican. In 2002, Karl Rove specifically told Republican legislators to run on that platform, and strength in the face of the terrorist threat is the basis of Bush’s reelection campaign. For that strategy to work, people need to be reminded constantly about the terrorist threat and how the current government is keeping them safe.

It has to be the right terrorist threat, though. Last month someone exploded a pipe bomb in a stem-cell research center near Boston, but the administration didn’t denounce this as a terrorist attack. In April 2003, the FBI disrupted a major terrorist plot in the U.S., arresting William Krar and seizing automatic weapons, pipe bombs, bombs disguised as briefcases, and at least one cyanide bomb—an actual chemical weapon. But because Krar was a member of a white supremacist group and not Muslim, Ashcroft didn’t hold a press conference, Tom Ridge didn’t announce how secure the homeland was, and Bush never mentioned it.

Threat warnings can be a potent tool in the fight against terrorism—when there is a specific threat at a specific moment. There are times when people need to act, and act quickly, in order to increase security. But this is a tool that can easily be abused, and when it’s abused it loses its effectiveness.

It’s instructive to look at the European countries that have been dealing with terrorism for decades, like the United Kingdom, Ireland, France, Italy, and Spain. None of these has a color-coded terror-alert system. None calls a press conference on the strength of “chatter.” Even Israel, which has seen more terrorism than any other nation in the world, issues terror alerts only when there is a specific imminent attack and they need people to be vigilant. And these alerts include specific times and places, with details people can use immediately. They’re not dissimilar from hurricane warnings.

A terror alert that instills a vague feeling of dread or panic echoes the very tactics of the terrorists. There are essentially two ways to terrorize people. The first is to do something spectacularly horrible, like flying airplanes into skyscrapers and killing thousands of people. The second is to keep people living in fear with the threat of doing something horrible. Decades ago, that was one of the IRA’s major aims. Inadvertently, the DHS is achieving the same thing.

There’s another downside to incessant threat warnings, one that happens when everyone realizes that they have been abused for political purposes. Call it the “Boy Who Cried Wolf” problem. After too many false alarms, the public will become inured to them. Already this has happened. Many Americans ignore terrorist threat warnings; many even ridicule them. The Bush administration lost considerable respect when it was revealed that August’s New York/Washington warning was based on three-year-old information. And the more recent warning that terrorists might target cheap prescription drugs from Canada was assumed universally to be politics-as-usual.

Repeated warnings do more harm than good, by needlessly creating fear and confusion among those who still trust the government, and anesthetizing everyone else to any future alerts that might be important. And every false alarm makes the next terror alert less effective.

Fighting global terrorism is difficult, and it’s not something that should be played for political gain. Countries that have been dealing with terrorism for decades have realized that much of the real work happens outside of public view, and that often the most important victories are the most secret. The elected officials of these countries take the time to explain this to their citizens, who in return have a realistic view of what the government can and can’t do to keep them safe.

By making terrorism the centerpiece of his reelection campaign, President Bush and the Republicans play a very dangerous game. They’re making many people needlessly fearful. They’re attracting the ridicule of others, both domestically and abroad. And they’re distracting themselves from the serious business of actually keeping Americans safe.

This article was originally published in the October 2004 edition of The Rake

Posted on October 4, 2004 at 7:08 PMView Comments

License Plate "Guns" and Privacy

New Haven police have a new law enforcement tool: a license-plate scanner. Similar to a radar gun, it reads the license plates of moving or parked cars and links with remote police databases, immediately providing information about the car and owner. Right now the police check if there are any taxes owed on the car, if the car or license plate is stolen, and if the car is unregistered or uninsured. A car that comes up positive is towed.

On the face of it, this is nothing new. The police have always been able to run a license plate. The difference is they would do it manually, and that limited its use. It simply wasn’t feasible for the police to run the plates of every car in a parking garage, or every car that passed through an intersection. What’s different isn’t the police tactic, but the efficiency of the process.

Technology is fundamentally changing the nature of surveillance. Years ago, surveillance meant trench-coated detectives following people down streets. It was laborious and expensive, and was only used when there was reasonable suspicion of a crime. Modern surveillance is the policeman with a license-plate scanner, or even a remote license-plate scanner mounted on a traffic light and a policeman sitting at a computer in the station. It’s the same, but it’s completely different. It’s wholesale surveillance.

And it disrupts the balance between the powers of the police and the rights of the people.

Wholesale surveillance is fast becoming the norm. New York’s E-Z Pass tracks cars at tunnels and bridges with tolls. We can all be tracked by our cell phones. Our purchases are tracked by banks and credit card companies, our telephone calls by phone companies, our Internet surfing habits by Web site operators. Security cameras are everywhere. If they wanted, the police could take the database of vehicles outfitted with the OnStar tracking system, and immediately locate all of those New Haven cars.

Like the license-plate scanners, the electronic footprints we leave everywhere can be automatically correlated with databases. The data can be stored forever, allowing police to conduct surveillance backwards in time.

The effects of wholesale surveillance on privacy and civil liberties is profound; but unfortunately, the debate often gets mischaracterized as a question about how much privacy we need to give up in order to be secure. This is wrong. It’s obvious that we are all safer when the police can use all techniques at their disposal. What we need are corresponding mechanisms to prevent abuse, and that don’t place an unreasonable burden on the innocent.

Throughout our nation’s history, we have maintained a balance between the necessary interests of police and the civil rights of the people. The license plate itself is such a balance. Imagine the debate from the early 1900s: The police proposed affixing a plaque to every car with the car owner’s name, so they could better track cars used in crimes. Civil libertarians objected because that would reduce the privacy of every car owner. So a compromise was reached: a random string of letter and numbers that the police could use to determine the car owner. By deliberately designing a more cumbersome system, the needs of law enforcement and the public’s right to privacy were balanced.

The search warrant process, as prescribed in the Fourth Amendment, is another balancing method. So is the minimization requirement for telephone eavesdropping: the police must stop listening to a phone line if the suspect under investigation is not talking.

For license-plate scanners, one obvious protection is to require the police to erase data collected on innocent car owners immediately, and not save it. The police have no legitimate need to collect data on everyone’s driving habits. Another is to allow car owners access to the information about them used in these automated searches, and to allow them to challenge inaccuracies.

We need to go further. Criminal penalties are severe in order to create a deterrent, because it is hard to catch wrongdoers. As they become easier to catch, a realignment is necessary. When the police can automate the detection of a wrongdoing, perhaps there should no longer be any criminal penalty attached. For example, both red light cameras and speed-trap cameras all issue citations without any “points” assessed against the driver.

Wholesale surveillance is not simply a more efficient way for the police to do what they’ve always done. It’s a new police power, one made possible with today’s technology and one that will be made easier with tomorrow’s. And with any new police power, we as a society need to take an active role in establishing rules governing its use. To do otherwise is to cede ever more authority to the police.

This essay was originally published in the New Haven Register.

Posted on October 4, 2004 at 7:05 PMView Comments

License Plate "Guns" and Privacy

New Haven police have a new law enforcement tool: a license-plate scanner. Similar to a radar gun, it reads the license plates of moving or parked cars and links with remote police databases, immediately providing information about the car and owner. Right now the police check if there are any taxes owed on the car, if the car or license plate is stolen, and if the car is unregistered or uninsured. A car that comes up positive is towed.

On the face of it, this is nothing new. The police have always been able to run a license plate. The difference is they would do it manually, and that limited its use. It simply wasn’t feasible for the police to run the plates of every car in a parking garage, or every car that passed through an intersection. What’s different isn’t the police tactic, but the efficiency of the process.

Technology is fundamentally changing the nature of surveillance. Years ago, surveillance meant trench-coated detectives following people down streets. It was laborious and expensive, and was only used when there was reasonable suspicion of a crime. Modern surveillance is the policeman with a license-plate scanner, or even a remote license-plate scanner mounted on a traffic light and a policeman sitting at a computer in the station. It’s the same, but it’s completely different. It’s wholesale surveillance.

And it disrupts the balance between the powers of the police and the rights of the people.

Wholesale surveillance is fast becoming the norm. New York’s E-Z Pass tracks cars at tunnels and bridges with tolls. We can all be tracked by our cell phones. Our purchases are tracked by banks and credit card companies, our telephone calls by phone companies, our Internet surfing habits by Web site operators. Security cameras are everywhere. If they wanted, the police could take the database of vehicles outfitted with the OnStar tracking system, and immediately locate all of those New Haven cars.

Like the license-plate scanners, the electronic footprints we leave everywhere can be automatically correlated with databases. The data can be stored forever, allowing police to conduct surveillance backwards in time.

The effects of wholesale surveillance on privacy and civil liberties is profound; but unfortunately, the debate often gets mischaracterized as a question about how much privacy we need to give up in order to be secure. This is wrong. It’s obvious that we are all safer when the police can use all techniques at their disposal. What we need are corresponding mechanisms to prevent abuse, and that don’t place an unreasonable burden on the innocent.

Throughout our nation’s history, we have maintained a balance between the necessary interests of police and the civil rights of the people. The license plate itself is such a balance. Imagine the debate from the early 1900s: The police proposed affixing a plaque to every car with the car owner’s name, so they could better track cars used in crimes. Civil libertarians objected because that would reduce the privacy of every car owner. So a compromise was reached: a random string of letter and numbers that the police could use to determine the car owner. By deliberately designing a more cumbersome system, the needs of law enforcement and the public’s right to privacy were balanced.

The search warrant process, as prescribed in the Fourth Amendment, is another balancing method. So is the minimization requirement for telephone eavesdropping: the police must stop listening to a phone line if the suspect under investigation is not talking.

For license-plate scanners, one obvious protection is to require the police to erase data collected on innocent car owners immediately, and not save it. The police have no legitimate need to collect data on everyone’s driving habits. Another is to allow car owners access to the information about them used in these automated searches, and to allow them to challenge inaccuracies.

We need to go further. Criminal penalties are severe in order to create a deterrent, because it is hard to catch wrongdoers. As they become easier to catch, a realignment is necessary. When the police can automate the detection of a wrongdoing, perhaps there should no longer be any criminal penalty attached. For example, both red light cameras and speed-trap cameras all issue citations without any “points” assessed against the driver.

Wholesale surveillance is not simply a more efficient way for the police to do what they’ve always done. It’s a new police power, one made possible with today’s technology and one that will be made easier with tomorrow’s. And with any new police power, we as a society need to take an active role in establishing rules governing its use. To do otherwise is to cede ever more authority to the police.

This essay was originally published in the New Haven Register.

Posted on October 4, 2004 at 7:05 PMView Comments

Academic Freedom and Security

Cryptography is the science of secret codes, and it is a primary Internet security tool to fight hackers, cyber crime, and cyber terrorism. CRYPTO is the world’s premier cryptography conference. It’s held every August in Santa Barbara.

This year, 400 people from 30 countries came to listen to dozens of talks. Lu Yi was not one of them. Her paper was accepted at the conference. But because she is a Chinese Ph.D. student in Switzerland, she was not able to get a visa in time to attend the conference.

In the three years since 9/11, the U.S. government has instituted a series of security measures at our borders, all designed to keep terrorists out. One of those measures was to tighten up the rules for foreign visas. Certainly this has hurt the tourism industry in the U.S., but the damage done to academic research is more profound and longer-lasting.

According to a survey by the Association of American Universities, many universities reported a drop of more than 10 percent in foreign student applications from last year. During the 2003 academic year, student visas were down 9 percent. Foreign applications to graduate schools were down 32 percent, according to another study by the Council of Graduate Schools.

There is an increasing trend for academic conferences, meetings and seminars to move outside of the United States simply to avoid visa hassles.

This affects all of high-tech, but ironically it particularly affects the very technologies that are critical in our fight against terrorism.

Also in August, on the other side of the country, the University of Connecticut held the second International Conference on Advanced Technologies for Homeland Security. The attendees came from a variety of disciplines—chemical trace detection, communications compatibility, X-ray scanning, sensors of various types, data mining, HAZMAT clothing, network intrusion detection, bomb diffusion, remote-controlled drones—and illustrate the enormous breadth of scientific know-how that can usefully be applied to counterterrorism.

It’s wrong to believe that the U.S. can conduct the research we need alone. At the Connecticut conference, the researchers presenting results included many foreigners studying at U.S. universities. Only 30 percent of the papers at CRYPTO had only U.S. authors. The most important discovery of the conference, a weakness in a mathematical function that protects the integrity of much of the critical information on the Internet, was made by four researchers from China.

Every time a foreign scientist can’t attend a U.S. technology conference, our security suffers. Every time we turn away a qualified technology graduate student, our security suffers. Technology is one of our most potent weapons in the war on terrorism, and we’re not fostering the international cooperation and development that is crucial for U.S. security.

Security is always a trade-off, and specific security countermeasures affect everyone, both the bad guys and the good guys. The new U.S. immigration rules may affect the few terrorists trying to enter the United States on visas, but they also affect honest people trying to do the same.

All scientific disciplines are international, and free and open information exchange—both in conferences and in academic programs at universities—will result in the maximum advance in the technologies vital to homeland security. The Soviet Union tried to restrict academic freedom along national lines, and it didn’t do the country any good. We should try not to follow in those footsteps.

This essay was originally published in the San Jose Mercury News

Posted on October 1, 2004 at 9:44 PMView Comments

Academic Freedom and Security

Cryptography is the science of secret codes, and it is a primary Internet security tool to fight hackers, cyber crime, and cyber terrorism. CRYPTO is the world’s premier cryptography conference. It’s held every August in Santa Barbara.

This year, 400 people from 30 countries came to listen to dozens of talks. Lu Yi was not one of them. Her paper was accepted at the conference. But because she is a Chinese Ph.D. student in Switzerland, she was not able to get a visa in time to attend the conference.

In the three years since 9/11, the U.S. government has instituted a series of security measures at our borders, all designed to keep terrorists out. One of those measures was to tighten up the rules for foreign visas. Certainly this has hurt the tourism industry in the U.S., but the damage done to academic research is more profound and longer-lasting.

According to a survey by the Association of American Universities, many universities reported a drop of more than 10 percent in foreign student applications from last year. During the 2003 academic year, student visas were down 9 percent. Foreign applications to graduate schools were down 32 percent, according to another study by the Council of Graduate Schools.

There is an increasing trend for academic conferences, meetings and seminars to move outside of the United States simply to avoid visa hassles.

This affects all of high-tech, but ironically it particularly affects the very technologies that are critical in our fight against terrorism.

Also in August, on the other side of the country, the University of Connecticut held the second International Conference on Advanced Technologies for Homeland Security. The attendees came from a variety of disciplines—chemical trace detection, communications compatibility, X-ray scanning, sensors of various types, data mining, HAZMAT clothing, network intrusion detection, bomb diffusion, remote-controlled drones—and illustrate the enormous breadth of scientific know-how that can usefully be applied to counterterrorism.

It’s wrong to believe that the U.S. can conduct the research we need alone. At the Connecticut conference, the researchers presenting results included many foreigners studying at U.S. universities. Only 30 percent of the papers at CRYPTO had only U.S. authors. The most important discovery of the conference, a weakness in a mathematical function that protects the integrity of much of the critical information on the Internet, was made by four researchers from China.

Every time a foreign scientist can’t attend a U.S. technology conference, our security suffers. Every time we turn away a qualified technology graduate student, our security suffers. Technology is one of our most potent weapons in the war on terrorism, and we’re not fostering the international cooperation and development that is crucial for U.S. security.

Security is always a trade-off, and specific security countermeasures affect everyone, both the bad guys and the good guys. The new U.S. immigration rules may affect the few terrorists trying to enter the United States on visas, but they also affect honest people trying to do the same.

All scientific disciplines are international, and free and open information exchange—both in conferences and in academic programs at universities—will result in the maximum advance in the technologies vital to homeland security. The Soviet Union tried to restrict academic freedom along national lines, and it didn’t do the country any good. We should try not to follow in those footsteps.

This essay was originally published in the San Jose Mercury News

Posted on October 1, 2004 at 9:44 PMView Comments

Keeping Network Outages Secret

There’s considerable confusion between the concept of secrecy and the concept of security, and it is causing a lot of bad security and some surprising political arguments. Secrecy is not the same as security, and most of the time secrecy contributes to a false feeling of security instead of to real security.

In June, the U.S. Department of Homeland Security urged regulators to keep network outage information secret. The Federal Communications Commission already requires telephone companies to report large disruptions of telephone service, and wants to extend that requirement to high-speed data lines and wireless networks. But the DHS fears that such information would give cyberterrorists a “virtual road map” to target critical infrastructures.

This sounds like the “full disclosure” debate all over again. Is publishing computer and network vulnerability information a good idea, or does it just help the hackers? It arises again and again, as malware takes advantage of software vulnerabilities after they’ve been made public.

The argument that secrecy is good for security is naive, and always worth rebutting. Secrecy is only beneficial to security in limited circumstances, and certainly not with respect to vulnerability or reliability information. Secrets are fragile; once they’re lost they’re lost forever. Security that relies on secrecy is also fragile; once secrecy is lost there’s no way to recover security. Trying to base security on secrecy is just plain bad design.

Cryptography is based on secrets—keys—but look at all the work that goes into making them effective. Keys are short and easy to transfer. They’re easy to update and change. And the key is the only secret component of a cryptographic system. Cryptographic algorithms make terrible secrets, which is why one of cryptography’s most basic principles is to assume that the algorithm is public.

That’s the other fallacy with the secrecy argument: the assumption that secrecy works. Do we really think that the physical weak points of networks are such a mystery to the bad guys? Do we really think that the hacker underground never discovers vulnerabilities?

Proponents of secrecy ignore the security value of openness: public scrutiny is the only reliable way to improve security. Before software bugs were routinely published, software companies routinely denied their existence and wouldn’t bother fixing them, believing in the security of secrecy. And because customers didn’t know any better, they bought these systems, believing them to be secure. If we return to a practice of keeping software bugs secret, we’ll have vulnerabilities known to a few in the security community and to much of the hacker underground.

Secrecy prevents people from assessing their own risks.

Public reporting of network outages forces telephone companies to improve their service. It allows consumers to compare the reliability of different companies, and to choose one that best serves their needs. Without public disclosure, companies could hide their reliability performance from the public.

Just look at who supports secrecy. Software vendors such as Microsoft want very much to keep vulnerability information secret. The Department of Homeland Security’s recommendations were loudly echoed by the phone companies. It’s the interests of these companies that are served by secrecy, not the interests of consumers, citizens, or society.

In the post-9/11 world, we’re seeing this clash of secrecy versus openness everywhere. The U.S. government is trying to keep details of many anti-terrorism countermeasures—and even routine government operations—secret. Information about the infrastructure of plants and government buildings is secret. Profiling information used to flag certain airline passengers is secret. The standards for the Department of Homeland Security’s color-coded terrorism threat levels are secret. Even information about government operations without any terrorism connections is being kept secret.

This keeps terrorists in the dark, especially “dumb” terrorists who might not be able to figure out these vulnerabilities on their own. But at the same time, the citizenry—to whom the government is ultimately accountable—is not allowed to evaluate the countermeasures, or comment on their efficacy. Security can’t improve because there’s no public debate or public education.

Recent studies have shown that most water, power, gas, telephone, data, transportation, and distribution systems are scale-free networks. This means they always have highly connected hubs. Attackers know this intuitively and go after the hubs. Defenders are beginning to learn how to harden the hubs and provide redundancy among them. Trying to keep it a secret that a network has hubs is futile. Better to identify and protect them.

We’re all safer when we have the information we need to exert market pressure on vendors to improve security. We would all be less secure if software vendors didn’t make their security vulnerabilities public, and if telephone companies didn’t have to report network outages. And when government operates without accountability, that serves the security interests of the government, not of the people.

Security Focus article
CNN article

Another version of this essay appeared in the October Communications of the ACM.

Posted on October 1, 2004 at 9:36 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.