Echoes of Sherlock Holmes

by Laurie R. King

  “You make it sound terribly irresponsible.”

  “That’s a rather mild way of putting it. But of course, we’re discussing the unintended consequences of all this business, and my visitor had come about the intended consequences: malware implantation. Watson, allow me to draw your attention to the very bottom of the deceptively dull document in your hand.”

  I read: “Could anyone take action on it without our agreement; e.g. could we be enabling the US to conduct a detention op which we would not consider permissible?” A cold grue ran down my spine.

  Holmes nodded sharply and took the paper back from me. “I see from your color and demeanor that you’ve alighted upon the key phrase, ‘detention op.’ I apologize for the discomfort this thought brings to mind, but I assure you it is germane to our present predicament.”

  My hands were shaking. Feigning a chill, I stuck them under my armpits, wrapping myself in a hug. My service in Afghanistan had left many scars, and not all of them showed. But the deepest one, the one that sometimes had me sitting bolt upright in the dead of night, screaming whilst tears coursed down my cheeks, could be triggered by those two words: detention op. I did not sign up to be an Army doctor expecting a pleasant enlistment. What I saw in Kandahar, though, was beyond my worst imaginings.

  “Take your time.” There was a rare and gentle note in my companion’s voice. It made me ashamed of my weakness.

  I cleared my throat, clasped my hands in my lap. “I’m fine, Holmes. Do go on.”

  After a significant look that left me even more ashamed, he did. “I said to my visitor, ‘I presume that you are here to discuss something related to this very last point?’ For as you no doubt perceived, Watson, the page there is wrinkled and has been smoothed again, as though a thumb had been driven into it by someone holding it tightly there.”

  I nodded, not trusting my voice.

  Holmes continued his tale.

  “I had done many of these insertions,” the man said, looking away from my eyes. “And the checklist had been something of a joke. Of course we knew that we could break something critical and tip off an alert systems administrator. Likewise, it was obvious that exposure would cause diplomatic embarrassment and could compromise our relationships with the tech companies who turned a blind eye to what we were doing. As to this last one, the business about detention ops, well, we always joked that the NSA was inside our decision loop, which is how the fourth-gen warfare types talk about leaks. Christ knows, we spent enough time trying to get inside their decision loop. The special relationship is all well and good, but at the end of the day, they’re them and we’re us and there’s plenty of room in that hyphen between Anglo and American.

  “But the truth was, there was always a chance the Americans would act on our intel in a way that would make us all want to hide our faces. Don’t get me wrong, Mr. Holmes, we’re no paragons of virtue. I’ve read the files on Sami al-Saadi and his wife, I know that we were in on that, supervising Gaddafi’s torturers. I don’t like that. But since the Troubles ended, we’ve done our evil retail, and the Americans deal wholesale. Whole airfleets devoted to ferrying people to torture camps that’re more like torture cities.

  “Have you ever read an intercept from a jihadi chat room, Mr. Holmes?”

  “Not recently.” He gave me a look to check if I was joking. I let him know I wasn’t.

  “The kids don’t have much by way of operational security. Loads of ’em use the same chat software they use with their mates, all in the clear, all ingested and indexed on Xkeyscore. Reading the intercepts is like being forced to listen to teenagers gossiping on a crowded bus: dirty jokes about mullahs whose dicks are so short they break their nose when they walk into a wall with a stiffie; trash talk about who’s real hard jihadi, who’s a jihobbyist, complaints about their parents and lovesick notes about their girlfriends and boyfriends, and loads of flirting. It’s no different to what we talked about when I was a boy, all bravado and rubbish.”

  “When you were a boy, you presumably didn’t talk about the necessity of wiping out all the kaffirs and establishing a caliphate, though.”

  “Fair point. Plenty of times, though, we fantasized about blowing up the old Comprehensive, especially come exams, and some of my mates would honestly have left a pipe-bomb under the stands when their teams were playing their arch-rivals, if they thought they’d have got away with it. Reading those transcripts, all I can think is, ‘There but for the grace of God . . .’

  “But they’re them and I’m me, and maybe one of ’em will get some truly bad ideas in his foolish head, and if I can catch him before then—” My visitor broke off then, staring at the fire. He opened and shut his mouth several times, clearly unable to find the words.

  I gave him a moment and then prompted, “But you found something?”

  He returned from whatever distant mental plain he’d been slogging over. “They wanted a big corpus to do information cascade analysis on. Part of a research project with one of the big unis, I won’t say which, but you can guess, I’m sure. They’d done a new rev on the stream analysis, they were able to detect a single user across multiple streams and signals from the upstream intercepts—I mean to say, they could tell which clicks and messages on the fiber-taps came from a given user, even if he was switching computers or IP addresses—they had a new tool for linking mobile data-streams to intercepts from laptops, which gives us location. They were marking it for long-term retention, indefinite retention, really.

  “I—”

  Here the fellow had to stop and look away again, and it was plain that he was reliving some difficult issue that he’d wrestled with his conscience over. “I was in charge of reviewing the truthed social graphs, sanity-checking the way that the algorithm believed their chain of command went against what I could see in the intercepts. But the reality is that those intercepts came from teenagers in a chat room. They didn’t have a chain of command—what the algorithm fingered as a command structure was really just the fact that some of them were better at arguing than others. One supposed lieutenant in the bunch was really the best comedian, the one who told the jokes they all repeated. To the algorithm, though, it looked like a command structure: subject emits a comm, timing shows that the comm cascades through an inner circle—his mates—to a wider circle. To a half-smart computer, this teenager in Leeds looked like Osama Junior.

  “I told them, of course. These were children with some bad ideas and too much braggadocio. Wannabes. If they were guilty of something, it was of being idiots. But for the researchers, this was even more exciting. The fact that their algorithm had detected an information cascade where there was no actual command structure meant that it had found a latent structure. It was like they set out knowing what they were going to find, and then whatever they found, they twisted until it fit their expectations.

  “Once we have the command structures all mapped out, everything becomes maths. You have a chart, neat circles and arrows pointing at each other, showing the information cascade. Who can argue with math? Numbers don’t lie. Having figured out their command structures from their chat rooms, we were able to map them over to their mobile communications, using the session identifiers the algorithm worked out.

  “These twerps were half-smart, just enough to be properly stupid. They’d bought burner phones from newsagents with prepaid SIMs and they only used them to call each other. People who try that sort of thing, they just don’t understand how data-mining works. When I’ve got a visualization of all the calls in a country, they’re mostly clustered in the middle, all tangled up with one another. You might call your mum and your girlfriend regular, might call a taxi company or the office a few times a week, make the odd call to a takeaway. Just looking at the vis, it’s really obvious what sort of number any number is: there’s the ‘pizza nodes,’ connected to hundreds of other nodes, obviously takeaways or minicabs. There’s TKs—telephone kiosks, which is what we call payphones—they’ve got their own signature pattern: lots of ov
erseas calls, calls to hotels, maybe a women’s shelter or A&E, the kinds of calls you make when you don’t have a mobile phone of your own.

  “It makes detecting anomalies dead easy. If a group of people converge on a site, turn off their phones, wait an hour and then turn ’em on again, well, that shows up. You don’t have to even be looking for that pattern. Just graph call activity, that sort of thing jumps straight out at you. Might as well go to your secret meeting with a brass band and a banner marked UP TO NO GOOD.

  “So think of the network graph now, all these nodes, most with a few lines going in and out, some pizza nodes with millions coming in and none going out, some TKs with loads going out and none coming in. And over here, off to the edge, where you couldn’t possibly miss it, all on its own, a fairy ring of six nodes, connected to each other and no one else. Practically a bullseye.

  “You don’t need to be looking for that pattern to spot it, but the lads from the uni and their GCHQ minders, they knew all about that pattern. Soon as they saw one that the persistence algorithm mapped onto the same accounts we’d seen in the chat rooms, they started to look at its information cascades. Those mapped right onto the cascade analysis from the chat intercepts, same flows, perfect. Course they did—because the kid who told the best jokes was the most sociable of the lot, he was the one who called the others when they weren’t in the chat, desperate for a natter.”

  I stopped him. “Thinking of your example of a group of phones that converge on a single location and all switch off together,” I said. “What about a group of friends who have a pact to turn off their phones whilst at dinner, to avoid distraction and interruption?”

  He nodded. “Happens. It’s rare, but ’course, not as rare as your actual terrorists. Our policy is, hard drives are cheap, add ’em all to long-term retention, have a human being look at their comms later and see whether we caught some dolphins in the tuna-net.”

  “I see.”

  “We have their ‘command structure,’ we have their secret phone numbers, so the next step is to have a little listen, which isn’t very hard, as I’m sure you can appreciate, Mr. Holmes.”

  “I make it a policy never to say anything over a telephone that I would regret seeing on the cover of the Times the next morning.”

  “A good policy, though one that I think I might have a hard time keeping myself,” I said, thinking of the number of times my poor Mary and I had indulged ourselves in a little playful, romantic talk when no one could hear.

  “Watson, if you find yourself tempted to have a breathy conversation with a ladyfriend over your mobile, I suggest you cool your ardor by contemplating the number of my brother’s young and impressionable associates who doubtlessly personally review every call you make. You’ve met my brother on a few occasions. Imagine what sort of man he would surround himself with.”

  I shuddered. I had no interest in women at that time, and memory of Mary was so fresh and painful that I couldn’t conceive of a time when that interest would return. But I had cherished the memories of those silly, loving, personal calls, times when it had felt like we were truly ourselves, letting the pretense fall away and showing each other the truth behind our habitual masks. The thought that those calls had been recorded, that someone might have listened in on them—“just to check” and make sure that we weren’t up to no good . . . It cast those cherished memories in a new light. I wouldn’t ever be able to think of them in the same way again.

  I was sure that Holmes had intuited my train of thought. He always could read me at a glance. He held my eye for a long moment and I sensed his sympathy. Somehow that made it worse.

  My guest (Holmes went on) began to pace, though I don’t think he realized he was doing it, so far away in memory was he.

  “The problem for the brain-boys was that these kids never said anything on their secret phones of any kind of interest. It was just a continuation of their online chat: talking trash, telling jokes, making fun of whoever wasn’t on the call. I wasn’t surprised, of course. I’d been reading their chat logs for months. They were just idiot kids. But for the spooks, this was just proof that they were doing their evil work using their apps. Damned if they do and if they didn’t: since it was all dirty jokes and messin’ on the voice chat, the bad stuff had to be in text.

  “These boys were playing secret agent. They bought their burner phones following a recipe they found online and the next step in the recipe was to download custom ROMs that only used encrypted filesystems and encrypted messaging and wouldn’t talk to the Google Play store or any other app store whose apps weren’t secure from the ground up. That meant that all their mobile comms were a black box to the smart boys.”

  “I imagine that’s where your checklist came in, then?”

  He grimaced. “Yeah. That OS they were using was good, and it updated itself all the time, trying to keep itself up to date as new bugs were discovered. But we knew that the NSA’s Tailored Access Operations group had some exploits for it that we could implant through their mobile carrier, which was a BT Mobile reseller, which meant they were running on EE’s network, which meant we could go in through T-Mobile. The NSA’s well inside of Deutsche Telekom. By man-in-the-middling their traffic, we could push an update that was signed by a certificate in their root of trust, one that Symantec had made before the Certificate Transparency days, that let us impersonate one of the trusted app vendors. From there, we owned their phones: took their mics and cameras, took their keystrokes, took all their comms.”

  “I suppose you discovered that they were actually plotting some heinous act of terror?”

  My visitor startled, then began to pace again. “How did you know?”

  “I know it because you told me. You came here, you handed me that extraordinary document. You would not have been here had the whole thing ended there. I can only infer that you exfiltrated data from their phones that caused our American cousins to take some rather rash action.”

  He dropped down on my sofa and put his face in his hands. “Thing was, it was just larking. I could tell. I’d been there. One of these boys had cousins in Pakistan who’d send him all sorts of bad ideas, talk to him about his jihad. It was the sort of thing that they could natter about endlessly; the things they’d do, when they worked themselves up to it. I’d done the same, you understand, when I was that age—played at Jason Bourne, tried to figure out the perfect crime.

  “They’d found their target, couple of US servicemen who’d had the bad sense to commute from the embassy to their places in the East End in uniform, passing through Liverpool Street Station every day. I suppose you know the station, Mr. Holmes, it’s practically a Call of Duty level, all those balconies and escalators and crisscrossing rail and tube lines. I can’t tell you how much time my friends and I spent planning assaults on places like that. That’s the thing, I recognized myself in them. I knew what they were about.

  “We must have been terrors when we were boys. The things we planned. The bombs. The carnage. We’d spend hours—days—debating the very best shrapnel—what would rip in a way that would make wounds that you couldn’t suture closed. We’d try and top each other, like kids telling horror stories to each other around the fire. But I know for an iron-clad fact that my best friend Lawrence went faint at the sight of actual blood.

  “The exploit we used to own their phones was American. It came from the NSA, from the Tailored Access Operations group. We had our own stuff, but the NSA were, you know, prolific. We have a toolbox; they’ve got a whole DIY store.

  “Do you know what’s meant by third-party collection?”

  “Of course.”

  “Well, I don’t, Holmes.”

  “Watson, you need to read your papers more closely. First- and second-party collection is data hoovered up by GCHQ and NSA and the Five Eyes, the so-called second parties. Third parties are all other collaborating nations that GCHQ and the NSA have partnerships with. Fourth-party collection is data that one security service takes by stealth from anothe
r security service. There’s fifth-party collection—one security service hacks another security service that’s hacked a third—and sixth-party collection and so forth and so on. Wheels within wheels.”

  “That all seems somehow perverse,” I said.

  “But it’s undeniably efficient. Why stalk your own prey when you can merely eat some other predator’s dinner out from under his nose, without him ever knowing it?”

  My visitor spoke of third-party collection, and I saw immediately where this was going. “They saw what you saw, in the lads’ communications. They read what you read.”

  “They did. Worse luck: they read what we wrote, what the analysts above my paygrade concluded about these idiot children, and then—”

  Here he rattled that paper again.

  “I see,” I said. “What, I wonder, do you suppose I might do for you at this juncture?”

  “It’s life in prison if I go public, Mr. Holmes. These kids, their parents are in the long-term Xkeyscore retention, all their communications, and they’re frantic. I read their emails to their relatives and each other, and I can only think of how I’d feel if my son had gone missing without a trace. These parents, they’re thinking that their kids have been snatched by paedos and are getting the Daily Mail front-page treatment. The truth, if they knew it, might terrify them even more. Far as I can work out, the NSA sent them to a CIA black site, the kind of place you wouldn’t wish on your worst enemy. The kind of place you build for revenge, not for intelligence.

  “It’s life in prison for me, or worse. But I can’t sit by and let this happen. I have this checklist and it told me that my job was to consider this very eventuality, and I did, and it came to pass anyway, and as far as I’m concerned, I have to do something now or I’m just as culpable as anyone. So I’ve come to you, Mr. Holmes, because before I go to prison for the rest of my life, before I deprive my own sons of their dad, forever, I want to know if there’s something I’m missing, some other way I can do the right thing here. Because I was brought up right, Mr. Holmes, and that means I don’t believe that my kids’ right to their father trumps those parents’ rights to their sons.”