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 • 43 Comments