Entries Tagged "keys"

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What is a Hacker?

A hacker is someone who thinks outside the box. It’s someone who discards conventional wisdom, and does something else instead. It’s someone who looks at the edge and wonders what’s beyond. It’s someone who sees a set of rules and wonders what happens if you don’t follow them. A hacker is someone who experiments with the limitations of systems for intellectual curiosity.

I wrote that last sentence in the year 2000, in my book Secrets and Lies. And I’m sticking to that definition.

This is what else I wrote in Secrets and Lies (pages 43-44):

Hackers are as old as curiosity, although the term itself is modern. Galileo was a hacker. Mme. Curie was one, too. Aristotle wasn’t. (Aristotle had some theoretical proof that women had fewer teeth than men. A hacker would have simply counted his wife’s teeth. A good hacker would have counted his wife’s teeth without her knowing about it, while she was asleep. A good bad hacker might remove some of them, just to prove a point.)

When I was in college, I knew a group similar to hackers: the key freaks. They wanted access, and their goal was to have a key to every lock on campus. They would study lockpicking and learn new techniques, trade maps of the steam tunnels and where they led, and exchange copies of keys with each other. A locked door was a challenge, a personal affront to their ability. These people weren’t out to do damage—stealing stuff wasn’t their objective—although they certainly could have. Their hobby was the power to go anywhere they wanted to.

Remember the phone phreaks of yesteryear, the ones who could whistle into payphones and make free phone calls. Sure, they stole phone service. But it wasn’t like they needed to make eight-hour calls to Manila or McMurdo. And their real work was secret knowledge: The phone network was a vast maze of information. They wanted to know the system better than the designers, and they wanted the ability to modify it to their will. Understanding how the phone system worked—that was the true prize. Other early hackers were ham-radio hobbyists and model-train enthusiasts.

Richard Feynman was a hacker; read any of his books.

Computer hackers follow these evolutionary lines. Or, they are the same genus operating on a new system. Computers, and networks in particular, are the new landscape to be explored. Networks provide the ultimate maze of steam tunnels, where a new hacking technique becomes a key that can open computer after computer. And inside is knowledge, understanding. Access. How things work. Why things work. It’s all out there, waiting to be discovered.

Computers are the perfect playground for hackers. Computers, and computer networks, are vast treasure troves of secret knowledge. The Internet is an immense landscape of undiscovered information. The more you know, the more you can do.

And it should be no surprise that many hackers have focused their skills on computer security. Not only is it often the obstacle between the hacker and knowledge, and therefore something to be defeated, but also the very mindset necessary to be good at security is exactly the same mindset that hackers have: thinking outside the box, breaking the rules, exploring the limitations of a system. The easiest way to break a security system is to figure out what the system’s designers hadn’t thought of: that’s security hacking.

Hackers cheat. And breaking security regularly involves cheating. It’s figuring out a smart card’s RSA key by looking at the power fluctuations, because the designers of the card never realized anyone could do that. It’s self-signing a piece of code, because the signature-verification system didn’t think someone might try that. It’s using a piece of a protocol to break a completely different protocol, because all previous security analysis only looked at protocols individually and not in pairs.

That’s security hacking: breaking a system by thinking differently.

It all sounds criminal: recovering encrypted text, fooling signature algorithms, breaking protocols. But honestly, that’s just the way we security people talk. Hacking isn’t criminal. All the examples two paragraphs above were performed by respected security professionals, and all were presented at security conferences.

I remember one conversation I had at a Crypto conference, early in my career. It was outside amongst the jumbo shrimp, chocolate-covered strawberries, and other delectables. A bunch of us were talking about some cryptographic system, including Brian Snow of the NSA. Someone described an unconventional attack, one that didn’t follow the normal rules of cryptanalysis. I don’t remember any of the details, but I remember my response after hearing the description of the attack.

“That’s cheating,” I said.

Because it was.

I also remember Brian turning to look at me. He didn’t say anything, but his look conveyed everything. “There’s no such thing as cheating in this business.”

Because there isn’t.

Hacking is cheating, and it’s how we get better at security. It’s only after someone invents a new attack that the rest of us can figure out how to defend against it.

For years I have refused to play the semantic “hacker” vs. “cracker” game. There are good hackers and bad hackers, just as there are good electricians and bad electricians. “Hacker” is a mindset and a skill set; what you do with it is a different issue.

And I believe the best computer security experts have the hacker mindset. When I look to hire people, I look for someone who can’t walk into a store without figuring out how to shoplift. I look for someone who can’t test a computer security program without trying to get around it. I look for someone who, when told that things work in a particular way, immediately asks how things stop working if you do something else.

We need these people in security, and we need them on our side. Criminals are always trying to figure out how to break security systems. Field a new system—an ATM, an online banking system, a gambling machine—and criminals will try to make an illegal profit off it. They’ll figure it out eventually, because some hackers are also criminals. But if we have hackers working for us, they’ll figure it out first—and then we can defend ourselves.

It’s our only hope for security in this fast-moving technological world of ours.

This essay appeared in the Summer 2006 issue of 2600.

Posted on September 14, 2006 at 7:13 AM • View Comments

Snake-Oil Research in Nature

Snake-oil isn’t only in commercial products. Here’s a piece of research published (behind a paywall) in Nature that’s just full of it.

The article suggests using chaos in an electro-optical system to generate a pseudo-random light sequence, which is then added to the message to protect it from interception. Now, the idea of using chaos to build encryption systems has been tried many times in the cryptographic community, and has always failed. But the authors of the Nature article show no signs of familiarity with prior cryptographic work.

The published system has the obvious problem that it does not include any form of message authentication, so it will be trivial to send spoofed messages or tamper with messages while they are in transit.

But a closer examination of the paper’s figures suggests a far more fundamental problem. There’s no key. Anyone with a valid receiver can decode the ciphertext. No key equals no security, and what you have left is a totally broken system.

I e-mailed Claudio R. Mirasso, the corresponding author, about the lack of any key, and got this reply: “To extract the message from the chaotic carrier you need to replicate the carrier itself. This can only be done by a laser that matches the emitter characteristics within, let’s say, within 2-5%. Semiconductor lasers with such similarity have to be carefully selected from the same wafer. Even though you have to test them because they can still be too different and do not synchronize. We talk abut a hardware key. Also the operating conditions (current, feedback length and coupling strength) are part of the key.”

Let me translate that. He’s saying that there is a hardware key baked into the system at fabrication. (It comes from manufacturing deviations in the lasers.) There’s no way to change the key in the field. There’s no way to recover security if any of the transmitters/receivers are lost or stolen. And they don’t know how hard it would be for an attacker to build a compatible receiver, or even a tunable receiver that could listen to a variety of encodings.

This paper would never get past peer review in any competent cryptography journal or conference. I’m surprised it was accepted in Nature, a fiercely competitive journal. I don’t know why Nature is taking articles on topics that are outside its usual competence, but it looks to me like Nature got burnt here by a lack of expertise in the area.

To be fair, the paper very carefully skirts the issue of security, and claims hardly anything: “Additionally, chaotic carriers offer a certain degree of intrinsic privacy, which could complement (via robust hardware encryption) both classical (software based) and quantum cryptography systems.” Now that “certain degree of intrinsic privacy” is approximately zero. But other than that, they’re very careful how they word their claims.

For instance, the abstract says: “Chaotic signals have been proposed as broadband information carriers with the potential of providing a high level of robustness and privacy in data transmission.” But there’s no disclosure that this proposal is bogus, from a privacy perspective. And the next-to-last paragraph says “Building on this, it should be possible to develop reliable cost-effective secure communication systems that exploit deeper properties of chaotic dynamics.” No disclosure that “chaotic dynamics” is actually irrelevant to the “secure” part. The last paragraph talks about “smart encryption techniques” (referencing a paper that talks about chaos encryption), “developing active eavesdropper-evasion strategies” (whatever that means), and so on. It’s just enough that if you don’t parse their words carefully and don’t already know the area well, you might come away with the impression that this is a major advance in secure communications. It seems as if it would have helped to have a more careful disclaimer.

Communications security was listed as one of the motivations for studying this communications technique. To list this as a motivation, without explaining that their experimental setup is actually useless for communications security, is questionable at best.

Meanwhile, the press has written articles that convey the wrong impression. Science News has an article that lauds this as a big achievement for communications privacy.

It talks about it as a “new encryption strategy,” “chaos-encrypted communication,” “1 gigabyte of chaos-encrypted information per second.” It’s obvious that the communications security aspect is what Science News is writing about. If the authors knew that their scheme is useless for communications security, they didn’t explain that very well.

There is also a New Scientist article titled “Let chaos keep your secrets safe” that characterizes this as a “new cryptographic technique, ” but I can’t get a copy of the full article.

Here are two more articles that discuss its security benefits. In the latter, Mirasso says “the main task we have for the future” is to “define, test, and calibrate the security that our system can offer.”

And their project web page says that “the continuous increase of computer speed threatens the safety” of traditional cryptography (which is bogus) and suggests using physical-layer chaos as a way to solve this. That’s listed as the goal of the project.

There’s a lesson here. This is research undertaken by researchers with no prior track record in cryptography, submitted to a journal with no background in cryptography, and reviewed by reviewers with who knows what kind of experience in cryptography. Cryptography is a subtle subject, and trying to design new cryptosystems without the necessary experience and training in the field is a quick route to insecurity.

And what’s up with Nature? Cryptographers with no training in physics know better than to think they are competent to evaluate physics research. If a physics paper were submitted to a cryptography journal, the authors would likely be gently redirected to a physics journal—we wouldn’t want our cryptography conferences to accept a paper on a subject they aren’t competent to evaluate. Why would Nature expect the situation to be any different when physicists try to do cryptography research?

Posted on December 7, 2005 at 6:36 AM • View Comments

RFID Car Keys

RFID car keys (subscription required) are becoming more popular. Since these devices broadcast a unique serial number, it’s only a matter of time before a significant percentage of the population can be tracked with them.

Lexus has made what it calls the “SmartAccess” keyless-entry system standard on its new IS sedans, designed to compete with German cars like the BMW 3 series or the Audi A4, as well as rivals such as the Infiniti G35 or the U.S.-made Cadillac CTS. BMW offers what it calls “keyless go” as an option on the new 3 series, and on its higher-priced 5, 6 and 7 series sedans.

Volkswagen AG’s Audi brand offers keyless-start systems on its A6 and A8 sedans, but not yet on U.S.-bound A4s. Cadillac’s new STS sedan, big brother to the CTS, also offers a pushbutton start.

Starter buttons have a racy flair—European sports cars and race cars used them in the past. The proliferation of starter buttons in luxury sedans has its roots in theft protection. An increasing number of cars now come with theft-deterrent systems that rely on a chip in the key fob that broadcasts a code to a receiver in the car. If the codes don’t match, the car won’t start.

Cryptography can be used to make these devices anonymous, but there’s no business reason for automobile manufacturers to field such a system. Once again, the economic barriers to security are far greater than the technical ones.

Posted on October 5, 2005 at 8:13 AM • View Comments

Fingerprint-Lock Failure in a Prison

So much for high-tech security:

Prison officers have been forced to abandon a new security system and return to the use of keys after the cutting-edge technology repeatedly failed.

The system, which is thought to have cost over £3 million, used fingerprint recognition to activate the locking system at the high-security Glenochil Prison near Tullibody, Clackmannanshire.

After typing in a PIN code, prison officers had to place their finger on a piece of glass. Once the print was recognised, they could then lock and unlock prison doors.

However, problems arose after a prisoner demonstrated to wardens that he could get through the system at will. Other prisoners had been doing the same for some time.

Unfortunately, the article doesn’t say how the prisoners hacked the system. Perhaps they lifed fingerprints off readers with transparent tape. Or perhaps the valid latent fingerprints left on the readers by wardens could be activated somehow.

I would really like some more details here. Does it really make sense to have a tokenless access system in a prison? I don’t know enough to answer that question.

Posted on September 26, 2005 at 4:03 PM • View Comments

Shoulder Surfing Keys

Here’s a criminal who “stole” keys, the physical metal ones, by examining images of them being used:

He surreptitiously videotaped letter carriers as they opened the boxes, zooming in on their keys. Lau used those images to calculate measurements for the grooves in the keys and created brass duplicates.

[…]

“The FBI is not aware of anything else like this,” bureau spokeswoman Jerri Williams said.

Technology causes security imbalances. Sometimes those imbalances favor the defender, and sometimes they favor the attacker. What we have here is a new application of a technology by an attacker.

Very clever.

Posted on September 7, 2005 at 11:35 AM • View Comments

The Keys to the Sydney Subway

Global secrets are generally considered poor security. The problems are twofold. One, you cannot apply any granularity to the security system; someone either knows the secret or does not. And two, global secrets are brittle. They fail badly; if the secret gets out, then the bad guys have a pretty powerful secret.

This is the situation right now in Sydney, where someone stole the master key that gives access to every train in the metropolitan area, and also starts them.

Unfortunately, this isn’t a thief who got lucky. It happened twice, and it’s possible that the keys were the target:

The keys, each of which could start every train, were taken in separate robberies within hours of each other from the North Shore Line although police believed the thefts were unrelated, a RailCorp spokeswoman said.

The first incident occurred at Gordon station when the driver of an empty train was robbed of the keys by two balaclava-clad men shortly after midnight on Sunday morning.

The second theft took place at Waverton Station on Sunday night when a driver was robbed of a bag, which contained the keys, she said.

So, what can someone do with the master key to the Sydney subway? It’s more likely a criminal than a terrorist, but even so it’s definitely a serious issue:

A spokesman for RailCorp told the paper it was taking the matter “very seriously,” but would not change the locks on its trains.

Instead, as of Sunday night, it had increased security around its sidings, with more patrols by private security guards and transit officers.

The spokesman said a “range of security measures” meant a train could not be stolen, even with the keys.

I don’t know if RailCorp should change the locks. I don’t know the risk: whether that “range of security measures” only protects against train theft—an unlikely scenario, if you ask me—or other potential scenarios as well. And I don’t know how expensive it would be to change the locks.

Another problem with global secrets is that it’s expensive to recover from a security failure.

And this certainly isn’t the first time a master key fell into the wrong hands:

Mr Graham said there was no point changing any of the metropolitan railway key locks.

“We could change locks once a week but I don’t think it reduces in any way the security threat as such because there are 2000 of these particular keys on issue to operational staff across the network and that is always going to be, I think, an issue.”

A final problem with global secrets is that it’s simply too easy to lose control of them.

Moral: Don’t rely on global secrets.

Posted on September 1, 2005 at 8:06 AM • View Comments

RFID Passport Security Revisited

I’ve written previously (including this op ed in the International Herald Tribune) about RFID chips in passports. An article in today’s USA Today (the paper version has a really good graphic) summarizes the latest State Department proposal, and it looks pretty good. They’re addressing privacy concerns, and they’re doing it right.

The most important feature they’ve included is an access-control system for the RFID chip. The data on the chip is encrypted, and the key is printed on the passport. The officer swipes the passport through an optical reader to get the key, and then the RFID reader uses the key to communicate with the RFID chip. This means that the passport-holder can control who has access to the information on the chip; someone cannot skim information from the passport without first opening it up and reading the information inside. Good security.

The new design also includes a thin radio shield in the cover, protecting the chip when the passport is closed. More good security.

Assuming that the RFID passport works as advertised (a big “if,” I grant you), then I am no longer opposed to the idea. And, more importantly, we have an example of an RFID identification system with good privacy safeguards. We should demand that any other RFID identification cards have similar privacy safeguards.

EDITED TO ADD: There’s more information in a Wired story:

The 64-KB chips store a copy of the information from a passport’s data page, including name, date of birth and a digitized version of the passport photo. To prevent counterfeiting or alterations, the chips are digitally signed….

“We are seriously considering the adoption of basic access control,” [Frank] Moss [the State Department’s deputy assistant secretary for passport services] said, referring to a process where chips remain locked until a code on the data page is first read by an optical scanner. The chip would then also transmit only encrypted data in order to prevent eavesdropping.

So it sounds like this access-control mechanism is not definite. In any case, I believe the system described in the USA Today article is a good one.

Posted on August 9, 2005 at 1:27 PM • View Comments

UK Police and Encryption

From The Guardian:

Police last night told Tony Blair that they need sweeping new powers to counter the terrorist threat, including the right to detain a suspect for up to three months without charge instead of the current 14 days….

They also want to make it a criminal offence for suspects to refuse to cooperate in giving the police full access to computer files by refusing to disclose their encryption keys.

On Channel 4 News today, Sir Ian Blair was asked why the police wanted to extend the time they could hold someone without charges from 14 days to 3 months. Part of his answer was that they sometimes needed to access encrypted computer files and 14 days was not enough time for them to break the encryption.

There’s something fishy going on here.

It’s certainly possible that password-guessing programs are more successful with three months to guess. But the Regulation of Investigatory Powers (RIP) Act, which went into effect in 2000, already allows the police to jail people who don’t surrender encryption keys:

If intercepted communications are encrypted (encoded and made secret), the act will force the individual to surrender the keys (pin numbers which allow users to decipher encoded data), on pain of jail sentences of up to two years.

Posted on July 27, 2005 at 3:00 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.