Another Interview
I was interviewed by MinnPost.
Page 452
Conspiracy Theories and the NSA
I’ve recently seen two articles speculating on the NSA’s capability, and practice, of spying on members of Congress and other elected officials. The evidence is all circumstantial and smacks of conspiracy thinking—and I have no idea whether any of it is true or not—but it’s a good illustration of what happens when trust in a public institution fails.
The NSA has repeatedly lied about the extent of its spying program. James R. Clapper, the director of national intelligence, has lied about it to Congress. Top-secret documents provided by Edward Snowden, and reported on by the Guardian and other newspapers, repeatedly show that the NSA’s surveillance systems are monitoring the communications of American citizens. The DEA has used this information to apprehend drug smugglers, then lied about it in court. The IRS has used this information to find tax cheats, then lied about it. It’s even been used to arrest a copyright violator. It seems that every time there is an allegation against the NSA, no matter how outlandish, it turns out to be true.
Guardian reporter Glenn Greenwald has been playing this well, dribbling the information out one scandal at a time. It’s looking more and more as if the NSA doesn’t know what Snowden took. It’s hard for someone to lie convincingly if he doesn’t know what the opposition actually knows.
All of this denying and lying results in us not trusting anything the NSA says, anything the president says about the NSA, or anything companies say about their involvement with the NSA. We know secrecy corrupts, and we see that corruption. There’s simply no credibility, and—the real problem—no way for us to verify anything these people might say.
It’s a perfect environment for conspiracy theories to take root: no trust, assuming the worst, no way to verify the facts. Think JFK assassination theories. Think 9/11 conspiracies. Think UFOs. For all we know, the NSA might be spying on elected officials. Edward Snowden said that he had the ability to spy on anyone in the U.S., in real time, from his desk. His remarks were belittled, but it turns out he was right.
This is not going to improve anytime soon. Greenwald and other reporters are still poring over Snowden’s documents, and will continue to report stories about NSA overreach, lawbreaking, abuses, and privacy violations well into next year. The “independent” review that Obama promised of these surveillance programs will not help, because it will lack both the power to discover everything the NSA is doing and the ability to relay that information to the public.
It’s time to start cleaning up this mess. We need a special prosecutor, one not tied to the military, the corporations complicit in these programs, or the current political leadership, whether Democrat or Republican. This prosecutor needs free rein to go through the NSA’s files and discover the full extent of what the agency is doing, as well as enough technical staff who have the capability to understand it. He needs the power to subpoena government officials and take their sworn testimony. He needs the ability to bring criminal indictments where appropriate. And, of course, he needs the requisite security clearance to see it all.
We also need something like South Africa’s Truth and Reconciliation Commission, where both government and corporate employees can come forward and tell their stories about NSA eavesdropping without fear of reprisal.
Yes, this will overturn the paradigm of keeping everything the NSA does secret, but Snowden and the reporters he’s shared documents with have already done that. The secrets are going to come out, and the journalists doing the outing are not going to be sympathetic to the NSA. If the agency were smart, it’d realize that the best thing it could do would be to get ahead of the leaks.
The result needs to be a public report about the NSA’s abuses, detailed enough that public watchdog groups can be convinced that everything is known. Only then can our country go about cleaning up the mess: shutting down programs, reforming the Foreign Intelligence Surveillance Act system, and reforming surveillance law to make it absolutely clear that even the NSA cannot eavesdrop on Americans without a warrant.
Comparisons are springing up between today’s NSA and the FBI of the 1950s and 1960s, and between NSA Director Keith Alexander and J. Edgar Hoover. We never managed to rein in Hoover’s FBI—it took his death for change to occur. I don’t think we’ll get so lucky with the NSA. While Alexander has enormous personal power, much of his power comes from the institution he leads. When he is replaced, that institution will remain.
Trust is essential for society to function. Without it, conspiracy theories naturally take hold. Even worse, without it we fail as a country and as a culture. It’s time to reinstitute the ideals of democracy: The government works for the people, open government is the best way to protect against government abuse, and a government keeping secrets from its people is a rare exception, not the norm.
This essay originally appeared on TheAtlantic.com.
The NSA's Cryptographic Capabilities
The latest Snowden document is the US intelligence “black budget.” There’s a lot of information in the few pages the Washington Post decided to publish, including an introduction by Director of National Intelligence James Clapper. In it, he drops a tantalizing hint: “Also, we are investing in groundbreaking cryptanalytic capabilities to defeat adversarial cryptography and exploit internet traffic.”
Honestly, I’m skeptical. Whatever the NSA has up its top-secret sleeves, the mathematics of cryptography will still be the most secure part of any encryption system. I worry a lot more about poorly designed cryptographic products, software bugs, bad passwords, companies that collaborate with the NSA to leak all or part of the keys, and insecure computers and networks. Those are where the real vulnerabilities are, and where the NSA spends the bulk of its efforts.
This isn’t the first time we’ve heard this rumor. In a WIRED article last year, longtime NSA-watcher James Bamford wrote:
According to another top official also involved with the program, the NSA made an enormous breakthrough several years ago in its ability to cryptanalyze, or break, unfathomably complex encryption systems employed by not only governments around the world but also many average computer users in the US.
We have no further information from Clapper, Snowden, or this other source of Bamford’s. But we can speculate.
Perhaps the NSA has some new mathematics that breaks one or more of the popular encryption algorithms: AES, Twofish, Serpent, triple-DES, Serpent. It wouldn’t be the first time this happened. Back in the 1970s, the NSA knew of a cryptanalytic technique called “differential cryptanalysis” that was unknown in the academic world. That technique broke a variety of other academic and commercial algorithms that we all thought secure. We learned better in the early 1990s, and now design algorithms to be resistant to that technique.
It’s very probable that the NSA has newer techniques that remain undiscovered in academia. Even so, such techniques are unlikely to result in a practical attack that can break actual encrypted plaintext.
The naive way to break an encryption algorithm is to brute-force the key. The complexity of that attack is 2n, where n is the key length. All cryptanalytic attacks can be viewed as shortcuts to that method. And since the efficacy of a brute-force attack is a direct function of key length, these attacks effectively shorten the key. So if, for example, the best attack against DES has a complexity of 239, that effectively shortens DES’s 56-bit key by 17 bits.
That’s a really good attack, by the way.
Right now the upper practical limit on brute force is somewhere under 80 bits. However, using that as a guide gives us some indication as to how good an attack has to be to break any of the modern algorithms. These days, encryption algorithms have, at a minimum, 128-bit keys. That means any NSA cryptanalytic breakthrough has to reduce the effective key length by at least 48 bits in order to be practical.
There’s more, though. That DES attack requires an impractical 70 terabytes of known plaintext encrypted with the key we’re trying to break. Other mathematical attacks require similar amounts of data. In order to be effective in decrypting actual operational traffic, the NSA needs an attack that can be executed with the known plaintext in a common MS-Word header: much, much less.
So while the NSA certainly has symmetric cryptanalysis capabilities that we in the academic world do not, converting that into practical attacks on the sorts of data it is likely to encounter seems so impossible as to be fanciful.
More likely is that the NSA has some mathematical breakthrough that affects one or more public-key algorithms. There are a lot of mathematical tricks involved in public-key cryptanalysis, and absolutely no theory that provides any limits on how powerful those tricks can be.
Breakthroughs in factoring have occurred regularly over the past several decades, allowing us to break ever-larger public keys. Much of the public-key cryptography we use today involves elliptic curves, something that is even more ripe for mathematical breakthroughs. It is not unreasonable to assume that the NSA has some techniques in this area that we in the academic world do not. Certainly the fact that the NSA is pushing elliptic-curve cryptography is some indication that it can break them more easily.
If we think that’s the case, the fix is easy: increase the key lengths.
Assuming the hypothetical NSA breakthroughs don’t totally break public-cryptography—and that’s a very reasonable assumption—it’s pretty easy to stay a few steps ahead of the NSA by using ever-longer keys. We’re already trying to phase out 1024-bit RSA keys in favor of 2048-bit keys. Perhaps we need to jump even further ahead and consider 3072-bit keys. And maybe we should be even more paranoid about elliptic curves and use key lengths above 500 bits.
One last blue-sky possibility: a quantum computer. Quantum computers are still toys in the academic world, but have the theoretical ability to quickly break common public-key algorithms—regardless of key length—and to effectively halve the key length of any symmetric algorithm. I think it extraordinarily unlikely that the NSA has built a quantum computer capable of performing the magnitude of calculation necessary to do this, but it’s possible. The defense is easy, if annoying: stick with symmetric cryptography based on shared secrets, and use 256-bit keys.
There’s a saying inside the NSA: “Cryptanalysis always gets better. It never gets worse.” It’s naive to assume that, in 2013, we have discovered all the mathematical breakthroughs in cryptography that can ever be discovered. There’s a lot more out there, and there will be for centuries.
And the NSA is in a privileged position: It can make use of everything discovered and openly published by the academic world, as well as everything discovered by it in secret.
The NSA has a lot of people thinking about this problem full-time. According to the black budget summary, 35,000 people and $11 billion annually are part of the Department of Defense-wide Consolidated Cryptologic Program. Of that, 4 percent—or $440 million—goes to “Research and Technology.”
That’s an enormous amount of money; probably more than everyone else on the planet spends on cryptography research put together. I’m sure that results in a lot of interesting—and occasionally groundbreaking—cryptanalytic research results, maybe some of it even practical.
Still, I trust the mathematics.
This essay originally appeared on Wired.com.
EDITED TO ADD: That was written before I could talk about this.
EDITED TO ADD: The Economist expresses a similar sentiment.
The NSA Is Breaking Most Encryption on the Internet
The new Snowden revelations are explosive. Basically, the NSA is able to decrypt most of the Internet. They’re doing it primarily by cheating, not by mathematics.
It’s joint reporting between the Guardian, the New York Times, and ProPublica.
I have been working with Glenn Greenwald on the Snowden documents, and I have seen a lot of them. These are my two essays on today’s revelations.
Remember this: The math is good, but math has no agency. Code has agency, and the code has been subverted.
EDITED TO ADD (9/6): Someone somewhere commented that the NSA’s “groundbreaking cryptanalytic capabilities” could include a practical attack on RC4. I don’t know one way or the other, but that’s a good speculation.
EDITED TO ADD (9/6): Relevant Slashdot and Reddit threads.
EDITED TO ADD (9/13): An opposing view to my call to action.
The Effect of Money on Trust
Money reduces trust in small groups, but increases it in larger groups. Basically, the introduction of money allows society to scale.
The team devised an experiment where subjects in small and large groups had the option to give gifts in exchange for tokens.
They found that there was a social cost to introducing this incentive. When all tokens were “spent”, a potential gift-giver was less likely to help than they had been in a setting where tokens had not yet been introduced.
The same effect was found in smaller groups, who were less generous when there was the option of receiving a token.
“Subjects basically latched on to monetary exchange, and stopped helping unless they received immediate compensation in a form of an intrinsically worthless object [a token].
“Using money does help large societies to achieve larger levels of co-operation than smaller societies, but it does so at a cost of displacing normal of voluntary help that is the bread and butter of smaller societies, in which everyone knows each other,” said Prof Camera.
But he said that this negative result was not found in larger anonymous groups of 32, instead co-operation increased with the use of tokens.
“This is exciting because we introduced something that adds nothing to the economy, but it helped participants converge on a behaviour that is more trustworthy.”
He added that the study reflected monetary exchange in daily life: “Global interaction expands the set of trade opportunities, but it dilutes the level of information about others’ past behaviour. In this sense, one can view tokens in our experiment as a parable for global monetary exchange.”
Journal of Homeland Security and Emergency Management
I keep getting alerts of new issues, but there are rarely articles I find interesting.
Human-Machine Trust Failures
I jacked a visitor’s badge from the Eisenhower Executive Office Building in Washington, DC, last month. The badges are electronic; they’re enabled when you check in at building security. You’re supposed to wear it on a chain around your neck at all times and drop it through a slot when you leave.
I kept the badge. I used my body as a shield, and the chain made a satisfying noise when it hit bottom. The guard let me through the gate.
The person after me had problems, though. Some part of the system knew something was wrong, and wouldn’t let her out. Eventually, the guard had to manually override something.
My point in telling this story is not to demonstrate how I beat the EEOB’s security—I’m sure the badge was quickly deactivated and showed up in some missing-badge log next to my name—but to illustrate how security vulnerabilities can result from human/machine trust failures. Something went wrong between when I went through the gate and when the person after me did. The system knew it but couldn’t adequately explain it to the guards. The guards knew it but didn’t know the details. Because the failure occurred when the person after me tried to leave the building, they assumed she was the problem. And when they cleared her of wrongdoing, they blamed the system.
In any hybrid security system, the human portion needs to trust the machine portion. To do so, both must understand the expected behavior for every state—how the system can fail and what those failures look like. The machine must be able to communicate its state and have the capacity to alert the humans when an expected state transition doesn’t happen as expected. Things will go wrong, either by accident or as the result of an attack, and the humans are going to need to troubleshoot the system in real time—that requires understanding on both parts. Each time things go wrong, and the machine portion doesn’t communicate well, the human portion trusts it a little less.
This problem is not specific to security systems, but inducing this sort of confusion is a good way to attack systems. When the attackers understand the system—especially the machine part—better than the humans in the system do, they can create a failure to exploit. Many social engineering attacks fall into this category. Failures also happen the other way. We’ve all experienced trust without understanding, when the human part of the system defers to the machine, even though it makes no sense: “The computer is always right.”
Humans and machines have different strengths. Humans are flexible and can do creative thinking in ways that machines cannot. But they’re easily fooled. Machines are more rigid and can handle state changes and process flows much better than humans can. But they’re bad at dealing with exceptions. If humans are to serve as security sensors, they need to understand what is being sensed. (That’s why “if you see something, say something” fails so often.) If a machine automatically processes input, it needs to clearly flag anything unexpected.
The more machine security is automated, and the more the machine is expected to enforce security without human intervention, the greater the impact of a successful attack. If this sounds like an argument for interface simplicity, it is. The machine design will be necessarily more complicated: more resilience, more error handling, and more internal checking. But the human/computer communication needs to be clear and straightforward. That’s the best way to give humans the trust and understanding they need in the machine part of any security system.
This essay previously appeared in IEEE Security & Privacy.
SHA-3 Status
NIST’s John Kelsey gave an excellent talk on the history, status, and future of the SHA-3 hashing standard. The slides are online.
EDITED TO ADD (9/14): A write-up of the talk.
Business Opportunities in Cloud Security
Bessemer Venture Partners partner David Cowan has an interesting article on the opportunities for cloud security companies.
Richard Stiennnon, an industry analyst, has a similar article.
And Zscaler comments on a 451 Research report on the cloud security business.
Syrian Electronic Army Cyberattacks
The Syrian Electronic Army attacked again this week, compromising the websites of the New York Times, Twitter, the Huffington Post, and others.
Political hacking isn’t new. Hackers were breaking into systems for political reasons long before commerce and criminals discovered the Internet. Over the years, we’ve seen U.K. vs. Ireland, Israel vs. Arab states, Russia vs. its former Soviet republics, India vs. Pakistan, and US vs. China.
There was a big one in 2007, when the government of Estonia was attacked in cyberspace following a diplomatic incident with Russia. It was hyped as the first cyberwar, but the Kremlin denied any Russian government involvement. The only individuals positively identified were young ethnic Russians living in Estonia.
Poke at any of these international incidents, and what you find are kids playing politics. The Syrian Electronic Army doesn’t seem to be an actual army. We don’t even know if they’re Syrian. And—to be fair—I don’t know their ages. Looking at the details of their attacks, it’s pretty clear they didn’t target the New York Times and others directly. They reportedly hacked into an Australian domain name registrar called Melbourne IT, and used that access to disrupt service at a bunch of big-name sites.
We saw this same tactic last year from Anonymous: hack around at random, then retcon a political reason why the sites they successfully broke into deserved it. It makes them look a lot more skilled than they actually are.
This isn’t to say that cyberattacks by governments aren’t an issue, or that cyberwar is something to be ignored. Attacks from China reportedly are a mix of government-executed military attacks, government-sponsored independent attackers, and random hacking groups that work with tacit government approval. The US also engages in active cyberattacks around the world. Together with Israel, the US employed a sophisticated computer virus (Stuxnet) to attack Iran in 2010.
For the typical company, defending against these attacks doesn’t require anything different than what you’ve been traditionally been doing to secure yourself in cyberspace. If your network is secure, you’re secure against amateur geopoliticians who just want to help their side.
This essay originally appeared on the Wall Street Journal’s website.
Sidebar photo of Bruce Schneier by Joe MacInnis.