I powered up the Xbox and watched as it came onto the screen. I was going to email Van and Jolu to tell them about the hassles with the cops, but as I put my fingers to the keyboard, I stopped again.
A feeling crept over me, one not unlike the feeling I’d had when I realized that they’d turned poor old Salmagundi into a traitor. This time, it was the feeling that my beloved Xnet might be broadcasting the location of every one of its users to the DHS.
It was what Dad had said:
The Xnet was secure because its users weren’t directly connected to the Internet. They hopped from Xbox to Xbox until they found one that was connected to the Internet, then they injected their material as undecipherable, encrypted data. No one could tell which of the Internet’s packets were Xnet and which ones were just plain old banking and e-commerce and other encrypted communication. You couldn’t find out who was tying the Xnet, let alone who was using the Xnet.
But what about Dad’s “Bayesian statistics?” I’d played with Bayesian math before. Darryl and I once tried to write our own better spam filter and when you filter spam, you need Bayesian math. Thomas Bayes was an 18th century British mathematician that no one cared about until a couple hundred years after he died, when computer scientists realized that his technique for statistically analyzing mountains of data would be super-useful for the modern world’s info-Himalayas.
Here’s some of how Bayesian stats work. Say you’ve got a bunch of spam. You take every word that’s in the spam and count how many times it appears. This is called a “word frequency histogram” and it tells you what the probability is that any bag of words is likely to be spam. Now, take a ton of email that’s not spam — in the biz, they call that “ham” — and do the same.
Wait until a new email arrives and count the words that appear in it. Then use the word-frequency histogram in the candidate message to calculate the probability that it belongs in the “spam” pile or the “ham” pile. If it turns out to be spam, you adjust the “spam” histogram accordingly. There are lots of ways to refine the technique — looking at words in pairs, throwing away old data — but this is how it works at core. It’s one of those great, simple ideas that seems obvious after you hear about it.
It’s got lots of applications — you can ask a computer to count the lines in a picture and see if it’s more like a “dog” line-frequency histogram or a “cat” line-frequency histogram. It can find porn, bank fraud, and flamewars. Useful stuff.
And it was bad news for the Xnet. Say you had the whole Internet wiretapped — which, of course, the DHS has. You can’t tell who’s passing Xnet packets by looking at the contents of those packets, thanks to crypto.
What you
This happens all the time in China. Some smart dissident will get the idea of getting around the Great Firewall of China, which is used to censor the whole country’s Internet connection, by using an encrypted connection to a computer in some other country. Now, the Party there can’t tell what the dissident is surfing: maybe it’s porn, or bomb-making instructions, or dirty letters from his girlfriend in the Philippines, or political material, or good news about Scientology. They don’t have to know. All they have to know is that this guy gets way more encrypted traffic than his neighbors. At that point, they send him to a forced labor camp just to set an example so that everyone can see what happens to smart-asses.
So far, I was willing to bet that the Xnet was under the DHS’s radar, but it wouldn’t be the case forever. And after tonight, I wasn’t sure that I was in any better shape than a Chinese dissident. I was putting all the people who signed onto the Xnet in jeopardy. The law didn’t care if you were actually doing anything bad; they were willing to put you under the microscope just for being statistically abnormal. And I couldn’t even stop it — now that the Xnet was running, it had a life of its own.
I was going to have to fix it some other way.
I wished I could talk to Jolu about this. He worked at an Internet Service Provider called Pigspleen Net that had hired him when he was twelve, and he knew way more about the net than I did. If anyone knew how to keep our butts out of jail, it would be him.
Luckily, Van and Jolu and I were planning to meet for coffee the next night at our favorite place in the Mission after school. Officially, it was our weekly Harajuku Fun Madness team meeting, but with the game canceled and Darryl gone, it was pretty much just a weekly weep-fest, supplemented by about six phone-calls and IMs a day that went, “Are you OK? Did it really happen?” It would be good to have something else to talk about.
“You’re out of your mind,” Vanessa said. “Are you actually, totally, really, for-real crazy or what?”
She had shown up in her girl’s school uniform because she’d been stuck going the long way home, all the way down to the San Mateo bridge then back up into the city, on a shuttle-bus service that her school was operating. She hated being seen in public in her gear, which was totally Sailor Moon — a pleated skirt and a tunic and knee- socks. She’d been in a bad mood ever since she turned up at the cafe, which was full of older, cooler, mopey emo art students who snickered into their lattes when she turned up.
“What do you want me to do, Van?” I said. I was getting exasperated myself. School was unbearable now that the game wasn’t on, now that Darryl was missing. All day long, in my classes, I consoled myself with the thought of seeing my team, what was left of it. Now we were fighting.
“I want you to stop putting yourself at risk, M1k3y.” The hairs on the back of my neck stood up. Sure, we always used our team handles at team meetings, but now that my handle was also associated with my Xnet use, it scared me to hear it said aloud in a public place.
“Don’t use that name in public anymore,” I snapped.
Van shook her head. “That’s just what I’m talking about. You could end up going to jail for this, Marcus, and not just you. Lots of people. After what happened to Darryl —”
“I’m doing this for Darryl!” Art students swiveled to look at us and I lowered my voice. “I’m doing this because the alternative is to let them get away with it all.”
“You think you’re going to stop them? You’re out of your mind. They’re the government.”
“It’s still our country,” I said. “We still have the right to do this.”
