Entries Tagged "essays"

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Quantum Computing and Cryptography

Quantum computing is a new way of computing—one that could allow humankind to perform computations that are simply impossible using today’s computing technologies. It allows for very fast searching, something that would break some of the encryption algorithms we use today. And it allows us to easily factor large numbers, something that would break the RSA cryptosystem for any key length.

This is why cryptographers are hard at work designing and analyzing “quantum-resistant” public-key algorithms. Currently, quantum computing is too nascent for cryptographers to be sure of what is secure and what isn’t. But even assuming aliens have developed the technology to its full potential, quantum computing doesn’t spell the end of the world for cryptography. Symmetric cryptography is easy to make quantum-resistant, and we’re working on quantum-resistant public-key algorithms. If public-key cryptography ends up being a temporary anomaly based on our mathematical knowledge and computational ability, we’ll still survive. And if some inconceivable alien technology can break all of cryptography, we still can have secrecy based on information theory—albeit with significant loss of capability.

At its core, cryptography relies on the mathematical quirk that some things are easier to do than to undo. Just as it’s easier to smash a plate than to glue all the pieces back together, it’s much easier to multiply two prime numbers together to obtain one large number than it is to factor that large number back into two prime numbers. Asymmetries of this kind—one-way functions and trap-door one-way functions—underlie all of cryptography.

To encrypt a message, we combine it with a key to form ciphertext. Without the key, reversing the process is more difficult. Not just a little more difficult, but astronomically more difficult. Modern encryption algorithms are so fast that they can secure your entire hard drive without any noticeable slowdown, but that encryption can’t be broken before the heat death of the universe.

With symmetric cryptography—the kind used to encrypt messages, files, and drives—that imbalance is exponential, and is amplified as the keys get larger. Adding one bit of key increases the complexity of encryption by less than a percent (I’m hand-waving here) but doubles the cost to break. So a 256-bit key might seem only twice as complex as a 128-bit key, but (with our current knowledge of mathematics) it’s 340,282,366,920,938,463,463,374,607,431,768,211,456 times harder to break.

Public-key encryption (used primarily for key exchange) and digital signatures are more complicated. Because they rely on hard mathematical problems like factoring, there are more potential tricks to reverse them. So you’ll see key lengths of 2,048 bits for RSA, and 384 bits for algorithms based on elliptic curves. Here again, though, the costs to reverse the algorithms with these key lengths are beyond the current reach of humankind.

This one-wayness is based on our mathematical knowledge. When you hear about a cryptographer “breaking” an algorithm, what happened is that they’ve found a new trick that makes reversing easier. Cryptographers discover new tricks all the time, which is why we tend to use key lengths that are longer than strictly necessary. This is true for both symmetric and public-key algorithms; we’re trying to future-proof them.

Quantum computers promise to upend a lot of this. Because of the way they work, they excel at the sorts of computations necessary to reverse these one-way functions. For symmetric cryptography, this isn’t too bad. Grover’s algorithm shows that a quantum computer speeds up these attacks to effectively halve the key length. This would mean that a 256-bit key is as strong against a quantum computer as a 128-bit key is against a conventional computer; both are secure for the foreseeable future.

For public-key cryptography, the results are more dire. Shor’s algorithm can easily break all of the commonly used public-key algorithms based on both factoring and the discrete logarithm problem. Doubling the key length increases the difficulty to break by a factor of eight. That’s not enough of a sustainable edge.

There are a lot of caveats to those two paragraphs, the biggest of which is that quantum computers capable of doing anything like this don’t currently exist, and no one knows when—or even if ­- we’ll be able to build one. We also don’t know what sorts of practical difficulties will arise when we try to implement Grover’s or Shor’s algorithms for anything but toy key sizes. (Error correction on a quantum computer could easily be an unsurmountable problem.) On the other hand, we don’t know what other techniques will be discovered once people start working with actual quantum computers. My bet is that we will overcome the engineering challenges, and that there will be many advances and new techniques­but they’re going to take time to discover and invent. Just as it took decades for us to get supercomputers in our pockets, it will take decades to work through all the engineering problems necessary to build large-enough quantum computers.

In the short term, cryptographers are putting considerable effort into designing and analyzing quantum-resistant algorithms, and those are likely to remain secure for decades. This is a necessarily slow process, as both good cryptanalysis transitioning standards take time. Luckily, we have time. Practical quantum computing seems to always remain “ten years in the future,” which means no one has any idea.

After that, though, there is always the possibility that those algorithms will fall to aliens with better quantum techniques. I am less worried about symmetric cryptography, where Grover’s algorithm is basically an upper limit on quantum improvements, than I am about public-key algorithms based on number theory, which feel more fragile. It’s possible that quantum computers will someday break all of them, even those that today are quantum resistant.

If that happens, we will face a world without strong public-key cryptography. That would be a huge blow to security and would break a lot of stuff we currently do, but we could adapt. In the 1980s, Kerberos was an all-symmetric authentication and encryption system. More recently, the GSM cellular standard does both authentication and key distribution—at scale—with only symmetric cryptography. Yes, those systems have centralized points of trust and failure, but it’s possible to design other systems that use both secret splitting and secret sharing to minimize that risk. (Imagine that a pair of communicants get a piece of their session key from each of five different key servers.) The ubiquity of communications also makes things easier today. We can use out-of-band protocols where, for example, your phone helps you create a key for your computer. We can use in-person registration for added security, maybe at the store where you buy your smartphone or initialize your Internet service. Advances in hardware may also help to secure keys in this world. I’m not trying to design anything here, only to point out that there are many design possibilities. We know that cryptography is all about trust, and we have a lot more techniques to manage trust than we did in the early years of the Internet. Some important properties like forward secrecy will be blunted and far more complex, but as long as symmetric cryptography still works, we’ll still have security.

It’s a weird future. Maybe the whole idea of number theory­-based encryption, which is what our modern public-key systems are, is a temporary detour based on our incomplete model of computing. Now that our model has expanded to include quantum computing, we might end up back to where we were in the late 1970s and early 1980s: symmetric cryptography, code-based cryptography, Merkle hash signatures. That would be both amusing and ironic.

Yes, I know that quantum key distribution is a potential replacement for public-key cryptography. But come on—does anyone expect a system that requires specialized communications hardware and cables to be useful for anything but niche applications? The future is mobile, always-on, embedded computing devices. Any security for those will necessarily be software only.

There’s one more future scenario to consider, one that doesn’t require a quantum computer. While there are several mathematical theories that underpin the one-wayness we use in cryptography, proving the validity of those theories is in fact one of the great open problems in computer science. Just as it is possible for a smart cryptographer to find a new trick that makes it easier to break a particular algorithm, we might imagine aliens with sufficient mathematical theory to break all encryption algorithms. To us, today, this is ridiculous. Public- key cryptography is all number theory, and potentially vulnerable to more mathematically inclined aliens. Symmetric cryptography is so much nonlinear muddle, so easy to make more complex, and so easy to increase key length, that this future is unimaginable. Consider an AES variant with a 512-bit block and key size, and 128 rounds. Unless mathematics is fundamentally different than our current understanding, that’ll be secure until computers are made of something other than matter and occupy something other than space.

But if the unimaginable happens, that would leave us with cryptography based solely on information theory: one-time pads and their variants. This would be a huge blow to security. One-time pads might be theoretically secure, but in practical terms they are unusable for anything other than specialized niche applications. Today, only crackpots try to build general-use systems based on one-time pads—and cryptographers laugh at them, because they replace algorithm design problems (easy) with key management and physical security problems (much, much harder). In our alien-ridden science-fiction future, we might have nothing else.

Against these godlike aliens, cryptography will be the only technology we can be sure of. Our nukes might refuse to detonate and our fighter jets might fall out of the sky, but we will still be able to communicate securely using one-time pads. There’s an optimism in that.

This essay originally appeared in IEEE Security and Privacy.

Posted on September 14, 2018 at 6:15 AM • View Comments

Don't Fear the TSA Cutting Airport Security. Be Glad That They're Talking about It.

Last week, CNN reported that the Transportation Security Administration is considering eliminating security at U.S. airports that fly only smaller planes—60 seats or fewer. Passengers connecting to larger planes would clear security at their destinations.

To be clear, the TSA has put forth no concrete proposal. The internal agency working group’s report obtained by CNN contains no recommendations. It’s nothing more than 20 people examining the potential security risks of the policy change. It’s not even new: The TSA considered this back in 2011, and the agency reviews its security policies every year. But commentary around the news has been strongly negative. Regardless of the idea’s merit, it will almost certainly not happen. That’s the result of politics, not security: Sen. Charles E. Schumer (D-N.Y.), one of numerous outraged lawmakers, has already penned a letter to the agency saying that “TSA documents proposing to scrap critical passenger security screenings, without so much as a metal detector in place in some airports, would effectively clear the runway for potential terrorist attacks.” He continued, “It simply boggles the mind to even think that the TSA has plans like this on paper in the first place.”

We don’t know enough to conclude whether this is a good idea, but it shouldn’t be dismissed out of hand. We need to evaluate airport security based on concrete costs and benefits, and not continue to implement security theater based on fear. And we should applaud the agency’s willingness to explore changes in the screening process.

There is already a tiered system for airport security, varying for both airports and passengers. Many people are enrolled in TSA PreCheck, allowing them to go through checkpoints faster and with less screening. Smaller airports don’t have modern screening equipment like full-body scanners or CT baggage screeners, making it impossible for them to detect some plastic explosives. Any would-be terrorist is already able to pick and choose his flight conditions to suit his plot.

Over the years, I have written many essays critical of the TSA and airport security, in general. Most of it is security theater—measures that make us feel safer without improving security. For example, the liquids ban makes no sense as implemented, because there’s no penalty for repeatedly trying to evade the scanners. The full-body scanners are terrible at detecting the explosive material PETN if it is well concealed—which is their whole point.

There are two basic kinds of terrorists. The amateurs will be deterred or detected by even basic security measures. The professionals will figure out how to evade even the most stringent measures. I’ve repeatedly said that the two things that have made flying safer since 9/11 are reinforcing the cockpit doors and persuading passengers that they need to fight back. Everything beyond that isn’t worth it.

It’s always possible to increase security by adding more onerous—and expensive—procedures. If that were the only concern, we would all be strip-searched and prohibited from traveling with luggage. Realistically, we need to analyze whether the increased security of any measure is worth the cost, in money, time and convenience. We spend $8 billion a year on the TSA, and we’d like to get the most security possible for that money.

This is exactly what that TSA working group was doing. CNN reported that the group specifically evaluated the costs and benefits of eliminating security at minor airports, saving $115 million a year with a “small (nonzero) undesirable increase in risk related to additional adversary opportunity.” That money could be used to bolster security at larger airports or to reduce threats totally removed from airports.

We need more of this kind of thinking, not less. In 2017, political scientists Mark Stewart and John Mueller published a detailed evaluation of airport security measures based on the cost to implement and the benefit in terms of lives saved. They concluded that most of what our government does either isn’t effective at preventing terrorism or is simply too expensive to justify the security it does provide. Others might disagree with their conclusions, but their analysis provides enough detailed information to have a meaningful argument.

The more we politicize security, the worse we are. People are generally terrible judges of risk. We fear threats in the news out of proportion with the actual dangers. We overestimate rare and spectacular risks, and underestimate commonplace ones. We fear specific “movie-plot threats” that we can bring to mind. That’s why we fear flying over driving, even though the latter kills about 35,000 people each year—about a 9/11’s worth of deaths each month. And it’s why the idea of the TSA eliminating security at minor airports fills us with fear. We can imagine the plot unfolding, only without Bruce Willis saving the day.

Very little today is immune to politics, including the TSA. It drove most of the agency’s decisions in the early years after the 9/11 terrorist attacks. That the TSA is willing to consider politically unpopular ideas is a credit to the organization. Let’s let them perform their analyses in peace.

This essay originally appeared in the Washington Post.

Posted on August 10, 2018 at 6:10 AM • View Comments

Russian Censorship of Telegram

Internet censors have a new strategy in their bid to block applications and websites: pressuring the large cloud providers that host them. These providers have concerns that are much broader than the targets of censorship efforts, so they have the choice of either standing up to the censors or capitulating in order to maximize their business. Today’s Internet largely reflects the dominance of a handful of companies behind the cloud services, search engines and mobile platforms that underpin the technology landscape. This new centralization radically tips the balance between those who want to censor parts of the Internet and those trying to evade censorship. When the profitable answer is for a software giant to acquiesce to censors’ demands, how long can Internet freedom last?

The recent battle between the Russian government and the Telegram messaging app illustrates one way this might play out. Russia has been trying to block Telegram since April, when a Moscow court banned it after the company refused to give Russian authorities access to user messages. Telegram, which is widely used in Russia, works on both iPhone and Android, and there are Windows and Mac desktop versions available. The app offers optional end-to-end encryption, meaning that all messages are encrypted on the sender’s phone and decrypted on the receiver’s phone; no part of the network can eavesdrop on the messages.

Since then, Telegram has been playing cat-and-mouse with the Russian telecom regulator Roskomnadzor by varying the IP address the app uses to communicate. Because Telegram isn’t a fixed website, it doesn’t need a fixed IP address. Telegram bought tens of thousands of IP addresses and has been quickly rotating through them, staying a step ahead of censors. Cleverly, this tactic is invisible to users. The app never sees the change, or the entire list of IP addresses, and the censor has no clear way to block them all.

A week after the court ban, Roskomnadzor countered with an unprecedented move of its own: blocking 19 million IP addresses, many on Amazon Web Services and Google Cloud. The collateral damage was widespread: The action inadvertently broke many other web services that use those platforms, and Roskomnadzor scaled back after it became clear that its action had affected services critical for Russian business. Even so, the censor is still blocking millions of IP addresses.

More recently, Russia has been pressuring Apple not to offer the Telegram app in its iPhone App Store. As of this writing, Apple has not complied, and the company has allowed Telegram to download a critical software update to iPhone users (after what the app’s founder called a delay last month). Roskomnadzor could further pressure Apple, though, including by threatening to turn off its entire iPhone app business in Russia.

Telegram might seem a weird app for Russia to focus on. Those of us who work in security don’t recommend the program, primarily because of the nature of its cryptographic protocols. In general, proprietary cryptography has numerous fatal security flaws. We generally recommend Signal for secure SMS messaging, or, if having that program on your computer is somehow incriminating, WhatsApp. (More than 1.5 billion people worldwide use WhatsApp.) What Telegram has going for it is that it works really well on lousy networks. That’s why it is so popular in places like Iran and Afghanistan. (Iran is also trying to ban the app.)

What the Russian government doesn’t like about Telegram is its anonymous broadcast feature­—channel capability and chats—­which makes it an effective platform for political debate and citizen journalism. The Russians might not like that Telegram is encrypted, but odds are good that they can simply break the encryption. Telegram’s role in facilitating uncontrolled journalism is the real issue.

Iran attempts to block Telegram have been more successful than Russia’s, less because Iran’s censorship technology is more sophisticated but because Telegram is not willing to go as far to defend Iranian users. The reasons are not rooted in business decisions. Simply put, Telegram is a Russian product and the designers are more motivated to poke Russia in the eye. Pavel Durov, Telegram’s founder, has pledged millions of dollars to help fight Russian censorship.

For the moment, Russia has lost. But this battle is far from over. Russia could easily come back with more targeted pressure on Google, Amazon and Apple. A year earlier, Zello used the same trick Telegram is using to evade Russian censors. Then, Roskomnadzor threatened to block all of Amazon Web Services and Google Cloud; and in that instance, both companies forced Zello to stop its IP-hopping censorship-evasion tactic.

Russia could also further develop its censorship infrastructure. If its capabilities were as finely honed as China’s, it would be able to more effectively block Telegram from operating. Right now, Russia can block only specific IP addresses, which is too coarse a tool for this issue. Telegram’s voice capabilities in Russia are significantly degraded, however, probably because high-capacity IP addresses are easier to block.

Whatever its current frustrations, Russia might well win in the long term. By demonstrating its willingness to suffer the temporary collateral damage of blocking major cloud providers, it prompted cloud providers to block another and more effective anti-censorship tactic, or at least accelerated the process. In April, Google and Amazon banned­—and technically blocked­—the practice of “domain fronting,” a trick anti-censorship tools use to get around Internet censors by pretending to be other kinds of traffic. Developers would use popular websites as a proxy, routing traffic to their own servers through another website­—in this case Google.com­—to fool censors into believing the traffic was intended for Google.com. The anonymous web-browsing tool Tor has used domain fronting since 2014. Signal, since 2016. Eliminating the capability is a boon to censors worldwide.

Tech giants have gotten embroiled in censorship battles for years. Sometimes they fight and sometimes they fold, but until now there have always been options. What this particular fight highlights is that Internet freedom is increasingly in the hands of the world’s largest Internet companies. And while freedom may have its advocates—­the American Civil Liberties Union has tweeted its support for those companies, and some 12,000 people in Moscow protested against the Telegram ban­—actions such as disallowing domain fronting illustrate that getting the big tech companies to sacrifice their near-term commercial interests will be an uphill battle. Apple has already removed anti-censorship apps from its Chinese app store.

In 1993, John Gilmore famously said that “The Internet interprets censorship as damage and routes around it.” That was technically true when he said it but only because the routing structure of the Internet was so distributed. As centralization increases, the Internet loses that robustness, and censorship by governments and companies becomes easier.

This essay previously appeared on Lawfare.com.

Posted on June 13, 2018 at 6:55 AM • View Comments

Router Vulnerability and the VPNFilter Botnet

On May 25, the FBI asked us all to reboot our routers. The story behind this request is one of sophisticated malware and unsophisticated home-network security, and it’s a harbinger of the sorts of pervasive threats ­ from nation-states, criminals and hackers ­ that we should expect in coming years.

VPNFilter is a sophisticated piece of malware that infects mostly older home and small-office routers made by Linksys, MikroTik, Netgear, QNAP and TP-Link. (For a list of specific models, click here.) It’s an impressive piece of work. It can eavesdrop on traffic passing through the router ­ specifically, log-in credentials and SCADA traffic, which is a networking protocol that controls power plants, chemical plants and industrial systems ­ attack other targets on the Internet and destructively “kill” its infected device. It is one of a very few pieces of malware that can survive a reboot, even though that’s what the FBI has requested. It has a number of other capabilities, and it can be remotely updated to provide still others. More than 500,000 routers in at least 54 countries have been infected since 2016.

Because of the malware’s sophistication, VPNFilter is believed to be the work of a government. The FBI suggested the Russian government was involved for two circumstantial reasons. One, a piece of the code is identical to one found in another piece of malware, called BlackEnergy, that was used in the December 2015 attack against Ukraine’s power grid. Russia is believed to be behind that attack. And two, the majority of those 500,000 infections are in Ukraine and controlled by a separate command-and-control server. There might also be classified evidence, as an FBI affidavit in this matter identifies the group behind VPNFilter as Sofacy, also known as APT28 and Fancy Bear. That’s the group behind a long list of attacks, including the 2016 hack of the Democratic National Committee.

Two companies, Cisco and Symantec, seem to have been working with the FBI during the past two years to track this malware as it infected ever more routers. The infection mechanism isn’t known, but we believe it targets known vulnerabilities in these older routers. Pretty much no one patches their routers, so the vulnerabilities have remained, even if they were fixed in new models from the same manufacturers.

On May 30, the FBI seized control of toknowall.com, a critical VPNFilter command-and-control server. This is called “sinkholing,” and serves to disrupt a critical part of this system. When infected routers contact toknowall.com, they will no longer be contacting a server owned by the malware’s creators; instead, they’ll be contacting a server owned by the FBI. This doesn’t entirely neutralize the malware, though. It will stay on the infected routers through reboot, and the underlying vulnerabilities remain, making the routers susceptible to reinfection with a variant controlled by a different server.

If you want to make sure your router is no longer infected, you need to do more than reboot it, the FBI’s warning notwithstanding. You need to reset the router to its factory settings. That means you need to reconfigure it for your network, which can be a pain if you’re not sophisticated in these matters. If you want to make sure your router cannot be reinfected, you need to update the firmware with any security patches from the manufacturer. This is harder to do and may strain your technical capabilities, though it’s ridiculous that routers don’t automatically download and install firmware updates on their own. Some of these models probably do not even have security patches available. Honestly, the best thing to do if you have one of the vulnerable models is to throw it away and get a new one. (Your ISP will probably send you a new one free if you claim that it’s not working properly. And you should have a new one, because if your current one is on the list, it’s at least 10 years old.)

So if it won’t clear out the malware, why is the FBI asking us to reboot our routers? It’s mostly just to get a sense of how bad the problem is. The FBI now controls toknowall.com. When an infected router gets rebooted, it connects to that server to get fully reinfected, and when it does, the FBI will know. Rebooting will give it a better idea of how many devices out there are infected.

Should you do it? It can’t hurt.

Internet of Things malware isn’t new. The 2016 Mirai botnet, for example, created by a lone hacker and not a government, targeted vulnerabilities in Internet-connected digital video recorders and webcams. Other malware has targeted Internet-connected thermostats. Lots of malware targets home routers. These devices are particularly vulnerable because they are often designed by ad hoc teams without a lot of security expertise, stay around in networks far longer than our computers and phones, and have no easy way to patch them.

It wouldn’t be surprising if the Russians targeted routers to build a network of infected computers for follow-on cyber operations. I’m sure many governments are doing the same. As long as we allow these insecure devices on the Internet ­ and short of security regulations, there’s no way to stop them ­ we’re going to be vulnerable to this kind of malware.

And next time, the command-and-control server won’t be so easy to disrupt.

This essay previously appeared in the Washington Post

EDITED TO ADD: The malware is more capable than we previously thought.

Posted on June 11, 2018 at 6:19 AM • View Comments

New Data Privacy Regulations

When Mark Zuckerberg testified before both the House and the Senate last month, it became immediately obvious that few US lawmakers had any appetite to regulate the pervasive surveillance taking place on the Internet.

Right now, the only way we can force these companies to take our privacy more seriously is through the market. But the market is broken. First, none of us do business directly with these data brokers. Equifax might have lost my personal data in 2017, but I can’t fire them because I’m not their customer or even their user. I could complain to the companies I do business with who sell my data to Equifax, but I don’t know who they are. Markets require voluntary exchange to work properly. If consumers don’t even know where these data brokers are getting their data from and what they’re doing with it, they can’t make intelligent buying choices.

This is starting to change, thanks to a new law in Vermont and another in Europe. And more legislation is coming.

Vermont first. At the moment, we don’t know how many data brokers collect data on Americans. Credible estimates range from 2,500 to 4,000 different companies. Last week, Vermont passed a law that will change that.

The law does several things to improve the security of Vermonters’ data, but several provisions matter to all of us. First, the law requires data brokers that trade in Vermonters’ data to register annually. And while there are many small local data brokers, the larger companies collect data nationally and even internationally. This will help us get a more accurate look at who’s in this business. The companies also have to disclose what opt-out options they offer, and how people can request to opt out. Again, this information is useful to all of us, regardless of the state we live in. And finally, the companies have to disclose the number of security breaches they’ve suffered each year, and how many individuals were affected.

Admittedly, the regulations imposed by the Vermont law are modest. Earlier drafts of the law included a provision requiring data brokers to disclose how many individuals’ data it has in its databases, what sorts of data it collects and where the data came from, but those were removed as the bill negotiated its way into law. A more comprehensive law would allow individuals to demand to exactly what information they have about them­—and maybe allow individuals to correct and even delete data. But it’s a start, and the first statewide law of its kind to be passed in the face of strong industry opposition.

Vermont isn’t the first to attempt this, though. On the other side of the country, Representative Norma Smith of Washington introduced a similar bill in both 2017 and 2018. It goes further, requiring disclosure of what kinds of data the broker collects. So far, the bill has stalled in the state’s legislature, but she believes it will have a much better chance of passing when she introduces it again in 2019. I am optimistic that this is a trend, and that many states will start passing bills forcing data brokers to be increasingly more transparent in their activities. And while their laws will be tailored to residents of those states, all of us will benefit from the information.

A 2018 California ballot initiative could help. Among its provisions, it gives consumers the right to demand exactly what information a data broker has about them. If it passes in November, once it takes effect, lots of Californians will take the list of data brokers from Vermont’s registration law and demand this information based on their own law. And again, all of us—regardless of the state we live in­—will benefit from the information.

We will also benefit from another, much more comprehensive, data privacy and security law from the European Union. The General Data Protection Regulation (GDPR) was passed in 2016 and took effect on 25 May. The details of the law are far too complex to explain here, but among other things, it mandates that personal data can only be collected and saved for specific purposes and only with the explicit consent of the user. We’ll learn who is collecting what and why, because companies that collect data are going to have to ask European users and customers for permission. And while this law only applies to EU citizens and people living in EU countries, the disclosure requirements will show all of us how these companies profit off our personal data.

It has already reaped benefits. Over the past couple of weeks, you’ve received many e-mails from companies that have you on their mailing lists. In the coming weeks and months, you’re going to see other companies disclose what they’re doing with your data. One early example is PayPal: in preparation for GDPR, it published a list of the over 600 companies it shares your personal data with. Expect a lot more like this.

Surveillance is the business model of the Internet. It’s not just the big companies like Facebook and Google watching everything we do online and selling advertising based on our behaviors; there’s also a large and largely unregulated industry of data brokers that collect, correlate and then sell intimate personal data about our behaviors. If we make the reasonable assumption that Congress is not going to regulate these companies, then we’re left with the market and consumer choice. The first step in that process is transparency. These new laws, and the ones that will follow, are slowly shining a light on this secretive industry.

This essay originally appeared in the Guardian.

Posted on June 8, 2018 at 6:48 AM • View Comments

E-Mail Vulnerabilities and Disclosure

Last week, researchers disclosed vulnerabilities in a large number of encrypted e-mail clients: specifically, those that use OpenPGP and S/MIME, including Thunderbird and AppleMail. These are serious vulnerabilities: An attacker who can alter mail sent to a vulnerable client can trick that client into sending a copy of the plaintext to a web server controlled by that attacker. The story of these vulnerabilities and the tale of how they were disclosed illustrate some important lessons about security vulnerabilities in general and e-mail security in particular.

But first, if you use PGP or S/MIME to encrypt e-mail, you need to check the list on this page and see if you are vulnerable. If you are, check with the vendor to see if they’ve fixed the vulnerability. (Note that some early patches turned out not to fix the vulnerability.) If not, stop using the encrypted e-mail program entirely until it’s fixed. Or, if you know how to do it, turn off your e-mail client’s ability to process HTML e-mail or—even better—stop decrypting e-mails from within the client. There’s even more complex advice for more sophisticated users, but if you’re one of those, you don’t need me to explain this to you.

Consider your encrypted e-mail insecure until this is fixed.

All software contains security vulnerabilities, and one of the primary ways we all improve our security is by researchers discovering those vulnerabilities and vendors patching them. It’s a weird system: Corporate researchers are motivated by publicity, academic researchers by publication credentials, and just about everyone by individual fame and the small bug-bounties paid by some vendors.

Software vendors, on the other hand, are motivated to fix vulnerabilities by the threat of public disclosure. Without the threat of eventual publication, vendors are likely to ignore researchers and delay patching. This happened a lot in the 1990s, and even today, vendors often use legal tactics to try to block publication. It makes sense; they look bad when their products are pronounced insecure.

Over the past few years, researchers have started to choreograph vulnerability announcements to make a big press splash. Clever names—the e-mail vulnerability is called “Efail“—websites, and cute logos are now common. Key reporters are given advance information about the vulnerabilities. Sometimes advance teasers are released. Vendors are now part of this process, trying to announce their patches at the same time the vulnerabilities are announced.

This simultaneous announcement is best for security. While it’s always possible that some organization—either government or criminal—has independently discovered and is using the vulnerability before the researchers go public, use of the vulnerability is essentially guaranteed after the announcement. The time period between announcement and patching is the most dangerous, and everyone except would-be attackers wants to minimize it.

Things get much more complicated when multiple vendors are involved. In this case, Efail isn’t a vulnerability in a particular product; it’s a vulnerability in a standard that is used in dozens of different products. As such, the researchers had to ensure both that everyone knew about the vulnerability in time to fix it and that no one leaked the vulnerability to the public during that time. As you can imagine, that’s close to impossible.

Efail was discovered sometime last year, and the researchers alerted dozens of different companies between last October and March. Some companies took the news more seriously than others. Most patched. Amazingly, news about the vulnerability didn’t leak until the day before the scheduled announcement date. Two days before the scheduled release, the researchers unveiled a teaser—honestly, a really bad idea—which resulted in details leaking.

After the leak, the Electronic Frontier Foundation posted a notice about the vulnerability without details. The organization has been criticized for its announcement, but I am hard-pressed to find fault with its advice. (Note: I am a board member at EFF.) Then, the researchers published—and lots of press followed.

All of this speaks to the difficulty of coordinating vulnerability disclosure when it involves a large number of companies or—even more problematic—communities without clear ownership. And that’s what we have with OpenPGP. It’s even worse when the bug involves the interaction between different parts of a system. In this case, there’s nothing wrong with PGP or S/MIME in and of themselves. Rather, the vulnerability occurs because of the way many e-mail programs handle encrypted e-mail. GnuPG, an implementation of OpenPGP, decided that the bug wasn’t its fault and did nothing about it. This is arguably true, but irrelevant. They should fix it.

Expect more of these kinds of problems in the future. The Internet is shifting from a set of systems we deliberately use—our phones and computers—to a fully immersive Internet-of-things world that we live in 24/7. And like this e-mail vulnerability, vulnerabilities will emerge through the interactions of different systems. Sometimes it will be obvious who should fix the problem. Sometimes it won’t be. Sometimes it’ll be two secure systems that, when they interact in a particular way, cause an insecurity. In April, I wrote about a vulnerability that arose because Google and Netflix make different assumptions about e-mail addresses. I don’t even know who to blame for that one.

It gets even worse. Our system of disclosure and patching assumes that vendors have the expertise and ability to patch their systems, but that simply isn’t true for many of the embedded and low-cost Internet of things software packages. They’re designed at a much lower cost, often by offshore teams that come together, create the software, and then disband; as a result, there simply isn’t anyone left around to receive vulnerability alerts from researchers and write patches. Even worse, many of these devices aren’t patchable at all. Right now, if you own a digital video recorder that’s vulnerable to being recruited for a botnet—remember Mirai from 2016?—the only way to patch it is to throw it away and buy a new one.

Patching is starting to fail, which means that we’re losing the best mechanism we have for improving software security at exactly the same time that software is gaining autonomy and physical agency. Many researchers and organizations, including myself, have proposed government regulations enforcing minimal security standards for Internet-of-things devices, including standards around vulnerability disclosure and patching. This would be expensive, but it’s hard to see any other viable alternative.

Getting back to e-mail, the truth is that it’s incredibly difficult to secure well. Not because the cryptography is hard, but because we expect e-mail to do so many things. We use it for correspondence, for conversations, for scheduling, and for record-keeping. I regularly search my 20-year e-mail archive. The PGP and S/MIME security protocols are outdated, needlessly complicated and have been difficult to properly use the whole time. If we could start again, we would design something better and more user friendly­but the huge number of legacy applications that use the existing standards mean that we can’t. I tell people that if they want to communicate securely with someone, to use one of the secure messaging systems: Signal, Off-the-Record, or—if having one of those two on your system is itself suspicious—WhatsApp. Of course they’re not perfect, as last week’s announcement of a vulnerability (patched within hours) in Signal illustrates. And they’re not as flexible as e-mail, but that makes them easier to secure.

This essay previously appeared on Lawfare.com.

Posted on June 4, 2018 at 6:33 AM • View Comments

Supply-Chain Security

Earlier this month, the Pentagon stopped selling phones made by the Chinese companies ZTE and Huawei on military bases because they might be used to spy on their users.

It’s a legitimate fear, and perhaps a prudent action. But it’s just one instance of the much larger issue of securing our supply chains.

All of our computerized systems are deeply international, and we have no choice but to trust the companies and governments that touch those systems. And while we can ban a few specific products, services or companies, no country can isolate itself from potential foreign interference.

In this specific case, the Pentagon is concerned that the Chinese government demanded that ZTE and Huawei add “backdoors” to their phones that could be surreptitiously turned on by government spies or cause them to fail during some future political conflict. This tampering is possible because the software in these phones is incredibly complex. It’s relatively easy for programmers to hide these capabilities, and correspondingly difficult to detect them.

This isn’t the first time the United States has taken action against foreign software suspected to contain hidden features that can be used against us. Last December, President Trump signed into law a bill banning software from the Russian company Kaspersky from being used within the US government. In 2012, the focus was on Chinese-made Internet routers. Then, the House Intelligence Committee concluded: “Based on available classified and unclassified information, Huawei and ZTE cannot be trusted to be free of foreign state influence and thus pose a security threat to the United States and to our systems.”

Nor is the United States the only country worried about these threats. In 2014, China reportedly banned antivirus products from both Kaspersky and the US company Symantec, based on similar fears. In 2017, the Indian government identified 42 smartphone apps that China subverted. Back in 1997, the Israeli company Check Point was dogged by rumors that its government added backdoors into its products; other of that country’s tech companies have been suspected of the same thing. Even al-Qaeda was concerned; ten years ago, a sympathizer released the encryption software Mujahedeen Secrets, claimed to be free of Western influence and backdoors. If a country doesn’t trust another country, then it can’t trust that country’s computer products.

But this trust isn’t limited to the country where the company is based. We have to trust the country where the software is written—and the countries where all the components are manufactured. In 2016, researchers discovered that many different models of cheap Android phones were sending information back to China. The phones might be American-made, but the software was from China. In 2016, researchers demonstrated an even more devious technique, where a backdoor could be added at the computer chip level in the factory that made the chips ­ without the knowledge of, and undetectable by, the engineers who designed the chips in the first place. Pretty much every US technology company manufactures its hardware in countries such as Malaysia, Indonesia, China and Taiwan.

We also have to trust the programmers. Today’s large software programs are written by teams of hundreds of programmers scattered around the globe. Backdoors, put there by we-have-no-idea-who, have been discovered in Juniper firewalls and D-Link routers, both of which are US companies. In 2003, someone almost slipped a very clever backdoor into Linux. Think of how many countries’ citizens are writing software for Apple or Microsoft or Google.

We can go even farther down the rabbit hole. We have to trust the distribution systems for our hardware and software. Documents disclosed by Edward Snowden showed the National Security Agency installing backdoors into Cisco routers being shipped to the Syrian telephone company. There are fake apps in the Google Play store that eavesdrop on you. Russian hackers subverted the update mechanism of a popular brand of Ukrainian accounting software to spread the NotPetya malware.

In 2017, researchers demonstrated that a smartphone can be subverted by installing a malicious replacement screen.

I could go on. Supply-chain security is an incredibly complex problem. US-only design and manufacturing isn’t an option; the tech world is far too internationally interdependent for that. We can’t trust anyone, yet we have no choice but to trust everyone. Our phones, computers, software and cloud systems are touched by citizens of dozens of different countries, any one of whom could subvert them at the demand of their government. And just as Russia is penetrating the US power grid so they have that capability in the event of hostilities, many countries are almost certainly doing the same thing at the consumer level.

We don’t know whether the risk of Huawei and ZTE equipment is great enough to warrant the ban. We don’t know what classified intelligence the United States has, and what it implies. But we do know that this is just a minor fix for a much larger problem. It’s doubtful that this ban will have any real effect. Members of the military, and everyone else, can still buy the phones. They just can’t buy them on US military bases. And while the US might block the occasional merger or acquisition, or ban the occasional hardware or software product, we’re largely ignoring that larger issue. Solving it borders on somewhere between incredibly expensive and realistically impossible.

Perhaps someday, global norms and international treaties will render this sort of device-level tampering off-limits. But until then, all we can do is hope that this particular arms race doesn’t get too far out of control.

This essay previously appeared in the Washington Post.

Posted on May 10, 2018 at 9:11 AM • View Comments

Securing Elections

Elections serve two purposes. The first, and obvious, purpose is to accurately choose the winner. But the second is equally important: to convince the loser. To the extent that an election system is not transparently and auditably accurate, it fails in that second purpose. Our election systems are failing, and we need to fix them.

Today, we conduct our elections on computers. Our registration lists are in computer databases. We vote on computerized voting machines. And our tabulation and reporting is done on computers. We do this for a lot of good reasons, but a side effect is that elections now have all the insecurities inherent in computers. The only way to reliably protect elections from both malice and accident is to use something that is not hackable or unreliable at scale; the best way to do that is to back up as much of the system as possible with paper.

Recently, there have been two graphic demonstrations of how bad our computerized voting system is. In 2007, the states of California and Ohio conducted audits of their electronic voting machines. Expert review teams found exploitable vulnerabilities in almost every component they examined. The researchers were able to undetectably alter vote tallies, erase audit logs, and load malware on to the systems. Some of their attacks could be implemented by a single individual with no greater access than a normal poll worker; others could be done remotely.

Last year, the Defcon hackers’ conference sponsored a Voting Village. Organizers collected 25 pieces of voting equipment, including voting machines and electronic poll books. By the end of the weekend, conference attendees had found ways to compromise every piece of test equipment: to load malicious software, compromise vote tallies and audit logs, or cause equipment to fail.

It’s important to understand that these were not well-funded nation-state attackers. These were not even academics who had been studying the problem for weeks. These were bored hackers, with no experience with voting machines, playing around between parties one weekend.

It shouldn’t be any surprise that voting equipment, including voting machines, voter registration databases, and vote tabulation systems, are that hackable. They’re computers—often ancient computers running operating systems no longer supported by the manufacturers—and they don’t have any magical security technology that the rest of the industry isn’t privy to. If anything, they’re less secure than the computers we generally use, because their manufacturers hide any flaws behind the proprietary nature of their equipment.

We’re not just worried about altering the vote. Sometimes causing widespread failures, or even just sowing mistrust in the system, is enough. And an election whose results are not trusted or believed is a failed election.

Voting systems have another requirement that makes security even harder to achieve: the requirement for a secret ballot. Because we have to securely separate the election-roll system that determines who can vote from the system that collects and tabulates the votes, we can’t use the security systems available to banking and other high-value applications.

We can securely bank online, but can’t securely vote online. If we could do away with anonymity—if everyone could check that their vote was counted correctly—then it would be easy to secure the vote. But that would lead to other problems. Before the US had the secret ballot, voter coercion and vote-buying were widespread.

We can’t, so we need to accept that our voting systems are insecure. We need an election system that is resilient to the threats. And for many parts of the system, that means paper.

Let’s start with the voter rolls. We know they’ve already been targeted. In 2016, someone changed the party affiliation of hundreds of voters before the Republican primary. That’s just one possibility. A well-executed attack that deletes, for example, one in five voters at random—or changes their addresses—would cause chaos on election day.

Yes, we need to shore up the security of these systems. We need better computer, network, and database security for the various state voter organizations. We also need to better secure the voter registration websites, with better design and better internet security. We need better security for the companies that build and sell all this equipment.

Multiple, unchangeable backups are essential. A record of every addition, deletion, and change needs to be stored on a separate system, on write-only media like a DVD. Copies of that DVD, or—even better—a paper printout of the voter rolls, should be available at every polling place on election day. We need to be ready for anything.

Next, the voting machines themselves. Security researchers agree that the gold standard is a voter-verified paper ballot. The easiest (and cheapest) way to achieve this is through optical-scan voting. Voters mark paper ballots by hand; they are fed into a machine and counted automatically. That paper ballot is saved, and serves as a final true record in a recount in case of problems. Touch-screen machines that print a paper ballot to drop in a ballot box can also work for voters with disabilities, as long as the ballot can be easily read and verified by the voter.

Finally, the tabulation and reporting systems. Here again we need more security in the process, but we must always use those paper ballots as checks on the computers. A manual, post-election, risk-limiting audit varies the number of ballots examined according to the margin of victory. Conducting this audit after every election, before the results are certified, gives us confidence that the election outcome is correct, even if the voting machines and tabulation computers have been tampered with. Additionally, we need better coordination and communications when incidents occur.

It’s vital to agree on these procedures and policies before an election. Before the fact, when anyone can win and no one knows whose votes might be changed, it’s easy to agree on strong security. But after the vote, someone is the presumptive winner—and then everything changes. Half of the country wants the result to stand, and half wants it reversed. At that point, it’s too late to agree on anything.

The politicians running in the election shouldn’t have to argue their challenges in court. Getting elections right is in the interest of all citizens. Many countries have independent election commissions that are charged with conducting elections and ensuring their security. We don’t do that in the US.

Instead, we have representatives from each of our two parties in the room, keeping an eye on each other. That provided acceptable security against 20th-century threats, but is totally inadequate to secure our elections in the 21st century. And the belief that the diversity of voting systems in the US provides a measure of security is a dangerous myth, because a few districts can be decisive and there are so few voting-machine vendors.

We can do better. In 2017, the Department of Homeland Security declared elections to be critical infrastructure, allowing the department to focus on securing them. On 23 March, Congress allocated $380m to states to upgrade election security.

These are good starts, but don’t go nearly far enough. The constitution delegates elections to the states but allows Congress to “make or alter such Regulations”. In 1845, Congress set a nationwide election day. Today, we need it to set uniform and strict election standards.

This essay originally appeared in the Guardian.

Posted on April 20, 2018 at 6:44 AM • View Comments

Facebook and Cambridge Analytica

In the wake of the Cambridge Analytica scandal, news articles and commentators have focused on what Facebook knows about us. A lot, it turns out. It collects data from our posts, our likes, our photos, things we type and delete without posting, and things we do while not on Facebook and even when we’re offline. It buys data about us from others. And it can infer even more: our sexual orientation, political beliefs, relationship status, drug use, and other personality traits—even if we didn’t take the personality test that Cambridge Analytica developed.

But for every article about Facebook’s creepy stalker behavior, thousands of other companies are breathing a collective sigh of relief that it’s Facebook and not them in the spotlight. Because while Facebook is one of the biggest players in this space, there are thousands of other companies that spy on and manipulate us for profit.

Harvard Business School professor Shoshana Zuboff calls it “surveillance capitalism.” And as creepy as Facebook is turning out to be, the entire industry is far creepier. It has existed in secret far too long, and it’s up to lawmakers to force these companies into the public spotlight, where we can all decide if this is how we want society to operate and—if not—what to do about it.

There are 2,500 to 4,000 data brokers in the United States whose business is buying and selling our personal data. Last year, Equifax was in the news when hackers stole personal information on 150 million people, including Social Security numbers, birth dates, addresses, and driver’s license numbers.

You certainly didn’t give it permission to collect any of that information. Equifax is one of those thousands of data brokers, most of them you’ve never heard of, selling your personal information without your knowledge or consent to pretty much anyone who will pay for it.

Surveillance capitalism takes this one step further. Companies like Facebook and Google offer you free services in exchange for your data. Google’s surveillance isn’t in the news, but it’s startlingly intimate. We never lie to our search engines. Our interests and curiosities, hopes and fears, desires and sexual proclivities, are all collected and saved. Add to that the websites we visit that Google tracks through its advertising network, our Gmail accounts, our movements via Google Maps, and what it can collect from our smartphones.

That phone is probably the most intimate surveillance device ever invented. It tracks our location continuously, so it knows where we live, where we work, and where we spend our time. It’s the first and last thing we check in a day, so it knows when we wake up and when we go to sleep. We all have one, so it knows who we sleep with. Uber used just some of that information to detect one-night stands; your smartphone provider and any app you allow to collect location data knows a lot more.

Surveillance capitalism drives much of the internet. It’s behind most of the “free” services, and many of the paid ones as well. Its goal is psychological manipulation, in the form of personalized advertising to persuade you to buy something or do something, like vote for a candidate. And while the individualized profile-driven manipulation exposed by Cambridge Analytica feels abhorrent, it’s really no different from what every company wants in the end. This is why all your personal information is collected, and this is why it is so valuable. Companies that can understand it can use it against you.

None of this is new. The media has been reporting on surveillance capitalism for years. In 2015, I wrote a book about it. Back in 2010, the Wall Street Journal published an award-winning two-year series about how people are tracked both online and offline, titled “What They Know.”

Surveillance capitalism is deeply embedded in our increasingly computerized society, and if the extent of it came to light there would be broad demands for limits and regulation. But because this industry can largely operate in secret, only occasionally exposed after a data breach or investigative report, we remain mostly ignorant of its reach.

This might change soon. In 2016, the European Union passed the comprehensive General Data Protection Regulation, or GDPR. The details of the law are far too complex to explain here, but some of the things it mandates are that personal data of EU citizens can only be collected and saved for “specific, explicit, and legitimate purposes,” and only with explicit consent of the user. Consent can’t be buried in the terms and conditions, nor can it be assumed unless the user opts in. This law will take effect in May, and companies worldwide are bracing for its enforcement.

Because pretty much all surveillance capitalism companies collect data on Europeans, this will expose the industry like nothing else. Here’s just one example. In preparation for this law, PayPal quietly published a list of over 600 companies it might share your personal data with. What will it be like when every company has to publish this sort of information, and explicitly explain how it’s using your personal data? We’re about to find out.

In the wake of this scandal, even Mark Zuckerberg said that his industry probably should be regulated, although he’s certainly not wishing for the sorts of comprehensive regulation the GDPR is bringing to Europe.

He’s right. Surveillance capitalism has operated without constraints for far too long. And advances in both big data analysis and artificial intelligence will make tomorrow’s applications far creepier than today’s. Regulation is the only answer.

The first step to any regulation is transparency. Who has our data? Is it accurate? What are they doing with it? Who are they selling it to? How are they securing it? Can we delete it? I don’t see any hope of Congress passing a GDPR-like data protection law anytime soon, but it’s not too far-fetched to demand laws requiring these companies to be more transparent in what they’re doing.

One of the responses to the Cambridge Analytica scandal is that people are deleting their Facebook accounts. It’s hard to do right, and doesn’t do anything about the data that Facebook collects about people who don’t use Facebook. But it’s a start. The market can put pressure on these companies to reduce their spying on us, but it can only do that if we force the industry out of its secret shadows.

This essay previously appeared on CNN.com.

EDITED TO ADD (4/2): Slashdot thread.

Posted on March 29, 2018 at 3:50 PM • View Comments

Artificial Intelligence and the Attack/Defense Balance

Artificial intelligence technologies have the potential to upend the longstanding advantage that attack has over defense on the Internet. This has to do with the relative strengths and weaknesses of people and computers, how those all interplay in Internet security, and where AI technologies might change things.

You can divide Internet security tasks into two sets: what humans do well and what computers do well. Traditionally, computers excel at speed, scale, and scope. They can launch attacks in milliseconds and infect millions of computers. They can scan computer code to look for particular kinds of vulnerabilities, and data packets to identify particular kinds of attacks.

Humans, conversely, excel at thinking and reasoning. They can look at the data and distinguish a real attack from a false alarm, understand the attack as it’s happening, and respond to it. They can find new sorts of vulnerabilities in systems. Humans are creative and adaptive, and can understand context.

Computers—so far, at least—are bad at what humans do well. They’re not creative or adaptive. They don’t understand context. They can behave irrationally because of those things.

Humans are slow, and get bored at repetitive tasks. They’re terrible at big data analysis. They use cognitive shortcuts, and can only keep a few data points in their head at a time. They can also behave irrationally because of those things.

AI will allow computers to take over Internet security tasks from humans, and then do them faster and at scale. Here are possible AI capabilities:

  • Discovering new vulnerabilities­—and, more importantly, new types of vulnerabilities­ in systems, both by the offense to exploit and by the defense to patch, and then automatically exploiting or patching them.
  • Reacting and adapting to an adversary’s actions, again both on the offense and defense sides. This includes reasoning about those actions and what they mean in the context of the attack and the environment.
  • Abstracting lessons from individual incidents, generalizing them across systems and networks, and applying those lessons to increase attack and defense effectiveness elsewhere.
  • Identifying strategic and tactical trends from large datasets and using those trends to adapt attack and defense tactics.

That’s an incomplete list. I don’t think anyone can predict what AI technologies will be capable of. But it’s not unreasonable to look at what humans do today and imagine a future where AIs are doing the same things, only at computer speeds, scale, and scope.

Both attack and defense will benefit from AI technologies, but I believe that AI has the capability to tip the scales more toward defense. There will be better offensive and defensive AI techniques. But here’s the thing: defense is currently in a worse position than offense precisely because of the human components. Present-day attacks pit the relative advantages of computers and humans against the relative weaknesses of computers and humans. Computers moving into what are traditionally human areas will rebalance that equation.

Roy Amara famously said that we overestimate the short-term effects of new technologies, but underestimate their long-term effects. AI is notoriously hard to predict, so many of the details I speculate about are likely to be wrong­—and AI is likely to introduce new asymmetries that we can’t foresee. But AI is the most promising technology I’ve seen for bringing defense up to par with offense. For Internet security, that will change everything.

This essay previously appeared in the March/April 2018 issue of IEEE Security & Privacy.

Posted on March 15, 2018 at 6:16 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.