Hey, everyone! So much for increasing the tempo, I guess. On the plus side, the parts where I wasn't tearing my hair out in frustration over not being able to put down a word for this (read: 90% of last month) were really fun. We'll return to Antonio Pope next chapter, I couldn't fit him into this one.
Oh, also, I'll be adding commentary at the end of chapters from here on. This will be technical / tactical explanations (because this helps cut down on the "Explain (thing) to Jaime" stuff and also reduces the googleing you guys need to do), character profiles (because, as you may have guessed, I'm going to shuffle around character traits and histories from the official versions to better fit what I'm trying to do) or a deeper look at some of the themes the stories deal with. If you're down with that, you'll get your first (and already overlong) dose here; if you don't care, you can safely skip it.
So, on with it!
---
Jaime found a seat just as the train rolled out of the station, the acceleration of its sudden start pushing her against the backrest. The car was almost empty, spare a few grungy tweens in the back.
"That was way too close," she whispered.
I must have asked for it, Nathan replied. Yeah, I absolutely did. Oh, train in two minutes, you'll never make it – just fyi, that was not an invitation to try, okay? I keep forgetting your complete lack of subtlety, but silly me, I'm sure I'll remember it after a few more stunts like this.
"No need to freak out," Jaime said tersely.
Is there anyone in the car with you? Are you talking to yourself in public?
In response, Jaime pulled the cellphone out of her jacket and slid it open. As far as she could tell, the youngsters (what a terrible word – she wasn't that much older, was she?) hadn't paid any attention to her at all.
"There, now I'm speaking on the phone," Jaime said. "Excuse me for being new to this."
Your inexperience I can handle, it's the intense helping of stupid I'm struggling with, Nathan said, sounding more frustrated than genuinely angry. Sommers, does the phrase "cellphone camera" mean anything to you? Are you, by any chance, familiar with a thing called YouTube? Maybe you have even heard about this hot new trend, blogging?
"I'm," Jaime began, then pinched the bridge of her nose. Her head was flooding with a dull, throbbing pain. "I'm really not in the mood for this. I just left my sister…"
Becca.
"…I just left Becca at home, all alone, and she doesn't even know that I'm out, or where I am." Jaime almost got up then and there. The voice in her head offered a solid appraisal of how to jump through the next large window and optimize her body position for a full-speed landing, but instead of going with the machine's flow, Jaime fought the urge and pointedly remained seated. "I lied to her," she said, more to herself than Nathan.
Yeah, that was impressive, Nathan said. We all had a nice front-row seat to that very emotional moment. Your sister's something else, Sommers; you really just wanna hug her and tell her everything's going to be alright with her and the world. So you did it! I have to admit, for a moment there, I thought the story wouldn't work, but you really sold it.
"That was pretty much the opposite of what I wanted to hear."
Oh. Oh! My bad, got my wires crossed, you wanted the "Sometimes you need to do bad things to protect the people you love" speech. Let's see…
"Ambrose…"
Oh, yeah, I got it, here goes: Sommers, sometimes you need to do bad things to protect the people you love. You know, for truth, justice and the American Way! Uh, well…I guess not so much truth, what with the lying, but my point is: Leave the scathing criticism of your every action to me, I'm better at it.
"Uh huh. Can you start supporting me now?"
I'm already updating your navigation with the federal buildings in town. And that's about it, right? I mean, do you need anything else? I could call a babysitter for Becca…
"No."
…or find you a theme song…
"No!"
Ah, okay, you want some me time, cool with me, I'll just shut up. You go enjoy that train ride. But don't forget to swipe your arm when you get out.
"Sure, Ambrose, whatever," Jaime said, rubbing her temples. "So, how did you get me through the turnstile?"
Maaaaa-gic! Nathan said. You owe me 10 bucks, by the way.
---
Will's next task (in the Herculean sense) was to shine his flashlight at Truewell without looking at her. It was just as well that he was still masked and in the dark, because his face was red with embarrassment – not over the naked skin Truewell was still working to cover up, but over his lapse in judgment. He was sitting a few feet away from her, resting the heavy bottles on his back against a fence. While his eyes burned holes into the night, he listened to duct tape being torn, ripped and smoothed out.
"Anthros?" Truewell asked, and he took that as an invitation to interrupt his penance stare. He chanced a look at her and found that she had repaired her suit with the liberal application of adhesive tape, but where the half-spent roll weighed lightly in her left hand, her protective mask was all the heavier in her right. "So," she said, "do I screw in a filter and put it back on?"
"I don't know," Will conceded, "but I don't think it would hurt. We need to get out of here anyway, maybe the agent has some sort of delayed onset, or it could be waiting for the next trigger, or –"
"I think we've established that you don't know."
"Sorry," Will said, shaking his head. "I'm just…this has been one bad call after another."
"The important thing is still that we get out," Truewell replied. "We need to find out what happened at the camp, find Madison, retrieve the filter from the safe room and report in."
"The camp," Will repeated absent-mindedly, "what about the camp?"
"Focus," Truewell said with a harsh twang. "The explosion that scared Madison came from the direction of the camp. There's no chatter on the radio, so something has gone very wrong."
"It's…broken."
It wasn't meant as an attack, but it hit Truewell anyway: a glance at her load-bearing gear showed the pouch for her radio crushed under the force of her fall.
"It just keeps getting better," Truewell exclaimed. "What is that beeping sound, anyway?"
Will's reaction was nothing so much as a clipped laugh, followed by a weary look at his wrist that only confirmed what he already knew.
"I'm almost out of air," he said.
"Take the mask off," Truewell said. "The fresh air is fine."
"We don't know that," he replied. "It hasn't killed you yet, but that doesn't mean…"
Truewell gave him a subtle look, the likes of which constituted a glare by her standards.
"You don't understand, Truewell," Will continued. "I'd love to pronounce it a miracle and dance the jig, but there's too many variables unaccounted for. There's a very real chance that you're going to die from exposure, sooner or later. If I take off the mask, I run the same risk. I'm not even sure if the filters would make any damn difference…and I'm tired. I'm really tired, Ruth, and I'm not sure if it's the stims or the running around or a symptom, but I can barely stay awake…"
"So your plan is to sit there and suffocate," she said.
"Oh, that's not…not the problem. I still have the backup bottle, you see, and that gives me another ten minutes, or something like that. So if you run and get the car, we should make it out of Paradise before my supply is completely empty. But every minute you're not looking for Madison, her chance of survival drops. Getting me to the base takes too much time, and you'd be nuts to go back into the hot zone afterwards…"
Truewell's next look was an honest-to-God glare. After a few pregnant seconds, she replied.
"Your radio works," she said, "establish contact with Berkut and the base. That should keep you awake. I'm going to get the car, drop you outside the town and go back for Madison."
"That's –"
"- and I'll be the judge of what's crazy around here, if you don't mind – William."
---
It was with no small amount of disbelief that Jaime found herself still hungry after wolfing down three hot dogs on the way from the BART station to the local FBI branch office. An impressive chunk of concrete and glass stretched before her, and sure steps led her to the front door of it. After wiping an errant spot of ketchup from the corner of her mouth, Jaime froze just a few steps shy of the door. Somehow, the thought of walking in there and pretending to be this secret agent character that gets casually waved through all checkpoints scared her.
With some more reflection, she might have figured out that the real nightmare scenario clinging to the back of her mind was trying just that, failing and being caught at it. As far as fears went, it wasn't wholly unfounded – she'd soon a lot of flash from Berkut, but were they really that connected? Only one way to find out, Jaime thought, and at once hated herself for it. So many risks…
"Yes, can I help you?" the receptionist said, a bit before Jaime realized she was inside, standing at the reception. The look on his face said everything about how well Jaime looked the part she had been assigned to play, but faced with the challenge, Jaime stiffened her posture and hardened her voice.
"Jaime Sommers, DoD," she said. "I was told to report here."
"ID, please."
And here's where it all falls apart, Jaime thought. Oh well, might as well play it up. With the barest hint of a smile, she reached into her jacket and produced her wallet. She would have found it reassuring if her hand had been shaking or slick with sweat, but instead it pulled out her driver's license and handed it to the receptionist with cold precision.
"One moment," he replied, and Jaime just stood there while the urge to jump through glass and run, run away homeward bound returned with a vengeance. Her breath slowed down as she shifted herself into a defensive frame of mind. What would the clerk do? If he went for the phone, it might be to call his boss and confirm her story…or it might be to call security. Or a gun, maybe…
Grab target head and slam against counter for high-probability stun SHUT UP SHUT UP.
What the receptionist actually produced was a bound book from a drawer in his desk. It was about an inch thick and bound in cheap imitation leather, with a blank cover and a whole lot of thin pages within. He opened it to about 20 pages south of its middle, frowned briefly and began flipping pages in search of his goal. Even from the distance and the book being, from Jaime's perspective, on its head, she could see that it was essentially a long list of names, ID numbers and two columns for signatures. Jaime's own name, scribbled with a painfully average amount of effort, appeared on as the final entry on the page the receptionist stopped at.
"Ah, there you are," he said, then handed the driver's license back to Jaime. "If you could sign here…"
Jaime signed the column reading Entered. The receptionist nodded his approval and replaced the book.
"Your escort will be here in a minute," he said. "Don't forget to sign out when you leave."
"Will do," Jaime replied.
---
In Berkut's operations center, Nathan raised his hands off the keyboard and leaned back into his chair. The telemetry displays on his screen slipped from his attention just as surely as the rest of the world. He folded his hands behind his head and closed his eyes.
"You have arrived at your destination," he spoke into his headset. "Thank you for flying with Ambrose Air. Scream if you need me, I'll have a smoke."
Given that it was, effectively, a massive bunker, smoking inside the underground facility at Wolf Creek was in theory frowned upon. Nothing like a lit cigarette could make it into one of the proper rooms – air pollution aside, the fire risk was just too great. Fortunately, the architecture of the facility with its free walkways and modules suspended in a large hollow shaft made it easy to step "outside" and enjoy your tobacco there, but even that posed its own difficulties. The walkways just weren't built to accommodate people standing around, so a small group of social smokers would end up blocking a route fairly quickly. This was made worse by the choice of walkway sections that had received a full shell upgrade into hallways, namely the paths and nodes close to the modules, while the open sections almost invariably were the actual bridges from the central modules to the outer rings, and those were built very narrow indeed. It had gotten bad enough that some enterprising facility management types had started to strip some hallway plates for an unending "maintenance" task, but none of those unsanctioned smoking places was particularly close to the operations center – presumably to keep the janitorial staff well away from Bledsoe's hunting grounds.
And so those places were of no interest to Nathan; he was perfectly content to stop walking at a point where his bad conscience over blocking an important route was just outweighed by his unwillingness to walk large distances for a cigarette break. The latter had the additional bonus of keeping him close to his station for emergencies, so what he ended up doing was to find the nearest section with no shell and light up one of his cancer sticks. His lighter flickered in the air current; the positive air pressure system serving the bunker was a serious machine for serious business, and easily generated a noticeable updraft in the vertical shaft. Nathan replaced the lighter in his pocket and grabbed another essential smoker's utensil from the inner breast pocket of his jacket: a portable ash tray. He'd seen people fired over tossing ash or cigarette butts onto the roofs of the medical labs down at the bottom of the shaft.
Nathan's breath sucked a cloud of smoke into his lungs, where the particles of burnt tobacco lingered for a few seconds. The release came slowly, twin streams of spent air from his nostrils. His eyes scanned his surroundings, flicking from side to side like the carriage of an inkjet printer. His right hand kept fussing with the cigarette; his left arm rested on the handrail of the walkway, keeping him stable against the hunched-over leaning pose he had instinctively assumed, as if he was just slightly taller than the person for whom the rail had been put there.
The cigarette disappeared into exactly eleven applications of ash and a butt over the course of three minutes, during which time nobody joined Nathan and no words were spoken. It would be wrong to say that Nathan thought about something during those three minutes, for he was the kind of person who thought the least when he looked the most lost in contemplation. Only memetic primitives and desires haunted his mindspace: whether to have another cigarette, whether to fetch some chewing gum from his shirt, or whether to just stand there until someone needed him.
But instead he pushed off the rail and walked back to the operations center. The fun couldn't last – not when he was on the clock, at least.
---
Staff Sergeant Anton Olivetti walked up to Jaime Sommers's car as inconspicuously as a middle-aged man in black clothes could. The guard detail for the newest Berkut recruit had been hastily reorganized after the demise slash dementation of the previous candidates, and Olivetti was completely aware that as far as jinxes and short sticks went, being one of the replacements rated fairly high. His confidence was only backed up by two comfortable delusions: one, that he was just a better soldier than either Mendelson or Brown, and two, that lightning doesn't strike in the same place twice.
He wasn't even in plainclothes; the expectation had been for him to sit in the oh-so-harmless van across the street and just watch the neighborhood, not to go out and actually do things. But out he was, with a bug detector in his right hand, and it was one of those moments when he wished that the "practical" guard uniform for Berkut soldiers was just a little more practical – for example, not being completely pitch black. What was wrong with a nice charcoal grey? It would have blended better into the night, Olivetti thought, and it would have looked less ominous.
He finally reached Jaime Sommers's car (that dark green SUV thing; right plates, too) and crouched down next to it. Olivetti wasn't the world's foremost authority on electronic surveillance equipment, but attaching a tracker to the underbody of a car wasn't much of a stretch; therefore, he thought it best to check there first.
The bug detector was an inoffensive little doodad the size of a small paperback, with little to it but a power switch, a series of LEDs and a dial on the side. Olivetti flicked it on and dialed the sensitivity down until the unit registered no more noise. Then, he swept it under the car experimentally. The tracker was almost insultingly easy to find, slapped beneath the passenger side door with double-sided adhesive tape. Olivetti removed the bug, found its power switch and turned it off. The little red LED on it stopped blinking.
He was almost ready to stand up and walk away, but remained crouched. A tracker like this wasn't expensive – and the attachment method wasn't exactly secure. "Anything worth one bug is worth two bugs," he mumbled to himself, and grinned. That's the way he'd do it, he reasoned. The detector continued its route underneath the car, quickly honing in on another signal from near the rear. With a triumphant smile, Olivetti walked around to the back of the car and reached under the bumper to strip another flimsy bug from the car. What he found instead was a smooth lump, hard beneath his fingers. He was about ready to dismiss that as an actual feature of the car's underbody and retry his search with the detector when he noticed a flicker of movement across his field of vision. Before the lizard part of his brain could even tell him "sudden movement = bad", he felt something tighten around his neck.
Sara Corvus was behind him, exercising a textbook rear blood choke on the Berkut soldier. Her left arm around his neck, with his adam's apple in the hollow of her elbow. Her right hand – with the cool texture of a latex glove on it – brushing against the rear of his neck. The only move it left him was to ram his left elbow into her ribs, but that had no effect one way or the other on the strength of her stranglehold.
"Yeah, that's gonna work," she whispered mockingly, her voice trailing off into infinity as time slowed down. Olivetti's world went monochrome, then black, and he felt himself hit the ground.
Corvus evaluated the situation quickly. The bug in Olivetti's hands was hers; one of her better friends had managed to slip it onto the car at the gas station. It was a pity that it couldn't have lasted longer, but it had served its purpose well – now she had Jaime's home address, and that was sure to be useful at some point. However, she had no plans for home intrusion. Placing some more surveillance gear nearby without being noticed by Jaime or one of Bledsoe's men would be quite the triumph for the night.
The bug detector in Olivetti's hand was still beeping. Corvus looked over her shoulder one more time and then climbed under the car. Her sight faded to shades of green and white against the darkness beneath, but the source of the signal stood out against the reflective sheen of the car's metallic underbody. It was a small blob of hardened resin, with a plastic disk the size of a quarter inside. It looked more like a movie prop than serious hardware, but the detector clearly read a signal coming from it. It made Corvus wish for her expanded toolkit – maybe she could have fried the electronics inside with a degaussing wand and then safely brought it home for analysis, but the best she could do there was to pry it out with a knife and stay away from important places until she figured out a way to switch it off without destroying it. The resin blob was a tough number, but it yielded to combat knife after a few attempts, chipping hardened epoxy all over her when she pried the bug free. With a look of satisfaction, she pocketed the bug and made to leave.
She almost got away with it. When she climbed out from beneath the car, nobody spotted her or Olivetti's body, and for a few seconds it looked like she might have just walked away from the scene with nobody the wiser. She even had her strut going, her thoughts on something else, and a smile on her lips – and then, across the street, somebody slammed a car door three times in two seconds. Either that, or there were three suppressed gunshots.
Corvus didn't like that interpretation, but it made a lot more sense.
Keeping her pace steady, she rounded the corner of Jaime's apartment building and considered her options. The gray van was the obvious Berkut surveillance unit, and the probable source of the shots. The street illumination made it difficult to approach the van without being seen – if anyone was watching. She leaned out of the corner, fixing the scene with her bionic eyes: nobody in the front cabin, no windows visible in any of the rear panels. The alternatives were to circle around, or to climb the building and jump across the street. Both would take time and risk exposure. But damn it, the situation was just too unstable to walk away from – no telling what someone after Berkut's stooges would do if left alone.
In light of all this, just running across the street seemed to be the path of least resistance.
She opened her coat and emerged from the shadows crouched, quickly and quietly darting from the corner to Jaime's car, taking care to stay concealed from the van's line of sight. After a few more explorative glances up and down the street – still no witnesses – she broke into a silent sprint across the street, darting through the lights as if doing the 100 meters through a minefield. The twin shoulder holsters of her pistols jostled with her steps, heavy reminders of the simple answer to most any problem.
Deep breaths. Corvus considered the guns again. Easy. But she didn't want to wake the neighbors.
Inside the van, she found the bloody body of a Berkut man, headset still slipped over his head and stretching its cable from his position on the floor to the computer console he had been using. Somewhat more interesting than that was the living occupant of the cabin, an older man with flecks of silver in his short-cropped black hair, matched by a black business suit and leather gloves. The entire getup was so self-consciously "intimidating" that it caused Corvus to underestimate him for a moment. It was enough for him to notice her and bring up his pistol; Corvus pounced on him, deflecting his shot by breaking his wrist. With her second move, she grabbed him by the neck and slammed him to the ground, with the same effort one might use to throw a pillow.
"Hi," Corvus said chirpily, "who the fuck are you?"
The man died. Corvus knew at once that she hadn't killed him, but the situation didn't allow her to dawdle around. She released her grip on the agent and took a step back. There didn't seem to be a way to do anything to the van without further endangering herself. Berkut was most likely already in the process of sending reinforcements, and loathe as Corvus was to admit it, they never did seem to run out of soldiers. With just her pistols, she didn't like the odds of her versus a full helicopter of goons. She couldn't take the stranger with her, either, but perhaps it was best to simply let Berkut figure out who he was and take a peek at their answers later.
She jumped out of the van and walked away. The line of people who wanted something to do with Jaime Sommers was getting longer, and Corvus would have to take some time to rethink her strategy.
---
Jaime could only start believing that she'd actually successfully impersonated a DoD analyst when she had passed through the security checkpoint into the building proper. The man who escorted her – a Special Agent Finlayson – was smaller than her mental image of a Nordic person, though the rest of the stereotype seemed to be fairly accurate. Cheap suit, though.
"So, what brings you to the Earlmayer case?" he asked, his voice tinged with a pronounced "clean" accent that made Jaime think of an comedian's impression of a sober news anchor.
"Having it dropped in my lap three hours ago," Jaime improvised, in what she thought was a not-all-that-terrible Midwestern twang. "All I've been told is that you have files relevant to it. My boss wants it, so he calls me up and says 'You got a date, now go fetch'."
Finlayson let out a small chortle. "My uncle was a Pentagon clerk in the 70s. He never got any fun business trips, either."
Look at this bullshit, Nathan's voice came. Broadcasting their SSID, but not to worry, they've got MAC filtering! Yeah, that's gonna keep me out. Jaime deduced that he was completely aware of her current inability to tell him to shut up, and that naturally led to flagrant abuse of technobabble privileges. I can't believe they've got this much off-peak traffic! Huh – only one client's getting it. Probably some idiot running a torrent. You know what? I'm gonna find out, and the betting pool starts here. My money's on bestiality. I can just imagine this fat, balding G-Man type who's got a thing for…
"So, uh, you do this a lot?" Finlayson asked as they walked down a drab hallway to the elevators. "Travel around, put out fires?"
"Not really. I'm fairly new to the game," Jaime said. "This was supposed to be my vacation, too."
"Ouch," Finlayson replied, twitching as if he had been hit by a biff on his shoulder.
" Yeah, that's the Department for you. Everything's time-critical, national security, 'I want it done yesterday' crap."
"It's not so bad here," Finlayson said. "To tell you the truth, I'm a paperwork kind of guy. I know a lot of people who get here and want to bust down doors, but give me a quiet, routine case any day of the week."
"I know exactly what you mean," Jaime replied with a smile.
Ah, to hear your bald-faced lies is a treat, Nathan's voice came. You should be in theater, or running a real estate fleece. I'd buy a timeshare from you! If…if I was an idiot, because, you know, timeshare, but if you find yourself a sucker, I'll print the brochures.
After an uneventful ride in the elevator (except for Nathan's continued play by play of cracking the network wide open), Finlayson swiped his access card to let Jaime into the building's archives. It was a large basement room stuffed with double-sided shelves full of file binders, all mounted on a rail system to let the shelves be moved and thereby squeeze more files into the same floor area. Jaime had to admit that this was at least tangentially related to sniffing around in a library, and her mind painted a vivid picture of an old, dusty file, all carefully laid out in double-spaced typing with black & white photos paperclipped to the pages. Instead, Finlayson led her to one of the desks in the room, stocked with a proper desktop, paper and pens as well as a computer dating from the early Clinton administration.
"It's really pretty user-friendly," Finlayson said of the electronic filing system, the aesthetic of which Jaime lacked the words to describe as anything other than old. "You just type in 'Roger Earlmayer' over there, then you hit F9, it'll show you the record with full transcriptions. You use the Page Up and Page Down keys to scroll in it; it'll also give you reference numbers if you want to look at the physical files. Need anything else?"
"No, I'm good," Jaime said. "Thank you, Agent Finlayson."
"No problem. I'll be here all night, so when you're done, just buzz up to Zach with the phone and he'll call me."
Jaime craned her head around to look at the wall next to the entrance. Fire alarm, fire extinguisher, phone, emergency evacuation procedures and map. Very official. She wondered if there was a proper Federal Bureau of Investigation way to put out a flaming trashcan.
"Zach?" she asked.
"Oh, he's…"
"The clerk at the front desk," Jaime guessed.
"Ah, yeah! Right," Finlayson said, rubbing the rear of his neck with his hand. "Sorry, we get a little loose in the graveyard shift."
"That's fine with me. Now, I don't want to keep you…"
"Oh, that's alright!"
"No, really…"
"My current perp died last week," Finlayson said. "It's not like he'll run away. But yeah, I'll stop bugging you now. I hope you find what you need."
"Thanks, Agent Finlayson," Jaime said with a smile.
The FBI man waved a silent goodbye, then turned and walked out of the archives. Jaime let her gaze sweep the room once again.
You alone? came Nathan's voice in her head. Check if there are cameras in the room.
Jaime determined, to her satisfaction, that there were none.
"Okay, now what the hell am I doing here?" she asked, a bit more sharply than she had intended.
Pretty good improv, Nathan said. But really, I just needed you inside the building. Bledsoe figured you'd think FBI when he said federal building, I spiked the nav to make sure.
"Does anyone in this outfit know how to give me a straightforward, direct order? Go here, do this? What the fuck is wrong with you people?"
Look, I get my orders, and when Bledsoe tells me to jump, I, uh, I say that my doctor told me to avoid putting stress on my ankles, but…well, you get what I mean, right?
"No."
Oh, Nathan said. But to answer your original question…
"Thank you, Ambrose."
…the FBI won't hand over personnel files to us without some heavy duty strings getting pulled, and we don't have the time to ask them nicely.
"Or at all," Jaime fired back. "But Berkut isn't good at getting permission, you guys just do things."
Ah, but it's easier to ask forgiveness than get permission. Also, technically, we. Better get used to guilt by association, Sommers. You might as well enjoy the perks.
"Oh no. You're not turning me into a jerk, too," Jaime protested. "Now, this Earlmayer stuff, do we actually…"
No. Call up the files and look at them real hard for their computer logs, but other than that…take notes, make origami cranes, whatever.
"Who is that guy, anyway?"
Arms dealer. Likes the good life a bit too much. Don't worry, small fish, not our problem.
"…why are we hacking the FBI network again?"
That's, uh, sorry, mission compartmentalization. Look, we got this, okay? And you did your part. Lean back and bask in the golden light of my brilliance.
Jaime Sommers rolled her eyes and sat down at the desk. After a moment of reflection, she buried her face in her hands and let out a deep sigh.
Tech Commentary: Wireless Security
First, to clarify, we'll only be dealing with Wireless LAN and RFID security today. You could cover eavesdropping on cellphone and radio conversations under the same banner, but let's leave those for another time.
When considering the security of WLAN, there are two basic approaches: restricting access, and encrypting content. Restricting access begins with a careful site survey to determine where the Access Point's signal can actually be picked up. Take note that, while most casual attackers may be working with low-gain "omnidirectional" antennas , passive signal sniffing can be done effectively with directional antennas that can pick up signals from great distances – with a clear line of sight and lack of interference, miles. Therefore, security-conscious users will try to reduce the signal strength of their Access Point to the minimum required to have the coverage they need. Paint, wallpapers and windows that are specifically designed to block radio signals in the 2.4 GHz band (where modern WLAN operates) are available, too. With enough of a budget, a wireless network can be built that covers an entire building floor yet radiates almost no useful signal to the outside world. Even in that case, however, one must still be wary of receivers brought into the building, either carried by visitors or hidden somewhere on the premises.
Two "softer" solutions are to disable SSID broadcast and enable MAC filtering. A network's SSID is used to identify it to the computers trying to access it; the reasoning goes that disabling broadcast will only allow computers to use the network if the user knows the SSID already. However, while this may stop casual scanning for networks, it doesn't actually hide the radio signals used, which can – if the attacker knows what he's looking for – be sniffed for data packets that contain the SSID. Once this happens, the attacker has the SSID ready to use and this feature becomes pointless. Similarly, MAC filtering only allows computers onto the network if their MAC address (a number designed to be unique for every piece of networking equipment) is specifically listed as having access – if your MAC doesn't match, you can't join the network. (This is what's called a "whitelist" security approach, by the way.) It can be defeated by sniffing for packets from a computer with legitimate access to the network and cloning its MAC address, which makes the attacker's computer indistinguishable from the one that was cloned, as far as the network infrastructure is concerned. However, if you actually start using this address, the cloned computer will receive a copy of all data you have requested and will discard it, having not actually sent the requests the network thinks are coming from it. If the volume of "unsolicited" data becomes high enough, this might degrade that computer's network speed to a noticeable degree, or – if it has a software firewall – trigger an alert about being subject to a denial of service attack. Either may tip off a clever/paranoid user that something is wrong.
Encrypting traffic on a wireless network is considered a necessity to establish any security – an unencrypted network is always in danger of simply having its packages sniffed passively, with no suspicious activity produced on the network itself. There are two acronyms to note here: WEP and WPA. Simply put, WEP is better than nothing, but where possible, a variant of WPA should be used.
To explain in more detail: WEP, or Wired Equivalent Privacy, was the first encryption standard widely used for wireless LAN applications. It uses a single key that must be known to all networked computers to encrypt all traffic through the network. Without that key, traffic can't be read or encrypted correctly. However, within months it emerged that the encryption algorithm was weak, allowing attackers to recover the key by sniffing the encrypted traffic and analyzing it. This requires several thousand network packets to be intercepted, which can take some time when passively sniffing a network with low activity. However, any network with high throughput can produce thousands of packets within a minute, and several outside attacks on a network can artificially induce high traffic, speeding up sniffing. So, why is WEP still in use? It is easy to implement and doesn't require much processing power, making it attractive for embedded devices that have to access the network. Further, some legacy devices may not support newer encryption standards. Furthermore, especially among private owners, widespread lack of knowledge and the perceived inconvenience of enabling security features on their network keep WEP or even completely open networks a common occurrence.
WPA, or Wi-Fi Protected Access, describes a small group of similar standards that are today considered adequate security for a Wireless LAN. You might deal with WPA or WPA2; the former is designed to be an easy upgrade for older hardware, the latter more secure. WPA can use the TKIP encryption algorithm; WPA 2 can use TKIP or AES (Advanced Encryption Standard). AES is considered superior, as TKIP has a known vulnerability that allows attackers to spoof some types of packets. Both WPA and WPA 2 support either a Personal variant (using a keyphrase, similar to WEP's setup) or an Enterprise variant that requires a separate authentication server. The "Personal" variant (also called PSK, pre-shared keyphrase) is vulnerable to brute-force attacks on that keyphrase, and dictionaries with common keyphrases exist to speed up this process. With recent advances in parallelizing attack algorithms and offloading them onto more suited hardware (the processors on graphics cards, called GPUs, are becoming popular), even a personal computer is capable of brute-forcing a simple keyphrase in days, and unlike other systems secured with passwords, the attack can take place without having to have direct access to the network. Simply having sniffed packets and trying to decrypt them with every possible keyphrase is enough.
Nathan's attack is against a WPA2-Enterprise system, which includes a separate authentication server in the network – a so-called RADIUS server. Among other technical details we won't get into, the key point of attack here is that RADIUS uses the MD5 algorithm to encrypt transmitted passwords. (Those are, in most configurations, simply the Windows passwords of the users.) MD5 is described as a hashing algorithm and is designed so that no two phrases will generate the same encrypted text (called a hash). However, it's not a serious encryption algorithm. With his privileged access to classified information, Nathan was able to generate a long master list of possible passwords built according to internal FBI recommendations; he then fed all those through MD5 and derived every possible hash. After capturing a few Access-Request data packets from the network (which contain both encrypted user names and passwords), all he had to do was compare his long master list against the hash in the packet and see if anything matched. (Of course, he also compared hashes of popular "private" passwords on the off-chance of finding a user who didn't follow policy. Yeah, what are the odds someone would choose a password that's easy to remember?) When the supercomputers at Wolf Creek found a match, Nathan could disguise his own access attempts as those of a legitimate user.
Depending on how complicated the user's password is, the attack's computational requirements range from "See WPA Personal, except even easier" to "If you don't know what a Teraflop is, don't even try". As for whether the user whose credentials Nathan stole was using a "secure" password or simply his wife's birthday: I'll leave that up to your imagination.
In conclusion: you wouldn't let an attacker plug his laptop into your cable LAN. Don't let them sniff the packets of your wireless network, either.
Finally, a look at the TransLink hack. While RFID (radio frequency ID) systems are becoming the new vogue in many applications, they are vulnerable (through little fault of anyone but the laws of physics) to certain attacks. One of the classics is the "Man in the Middle"-attack. Simply put, it requires the attacker to get between the sender and the receiver of a communication, intercept all messages and then send them to their intended destination. In this way, the attacker becomes capable of reading and manipulating the messages sent. All important communications are therefore routinely encrypted and hashed, which makes them hard to read for attackers and any attempts to change the message obvious. However, for simple applications, an effective attack can consist simply of recording the messages sent between two devices and playing them back at a time of the attacker's choosing.
The TransLink terminal queries for TransLink cards in the vicinity (and by in the vicinity we mean a distance no larger than a few inches); cards respond by sending a message back. The entire process derives most of its security from the extremely short distances involved – it's hard to pick up those signals without being noticed. One theoretical attack would be to replicate the query of the reader and walk through a station to collect the responses from nearby cards; similar attacks have been demonstrated against RFID-equipped passports, for example. However, all Nathan had to do to set this hack up was to keep a signal recorder close to his TransLink card when he swiped it once, and record the handshake between receiver and card. After that, he knows the right signal to send in response to the receiver's query, and can send it from any device capable of simulating an RFID chip, such as the antenna array in Jaime's bionic arm. This kind of duplication is called "cloning". After that, he never used the proper TransLink card again – the concept of carrying an electronic device he doesn't have full control over didn't sit well with him. (Also, he doesn't ride the BART much these days.)
However, this particular implementation of RFID won't actually let him cheat the system out of money: all that's encoded on a card is the account number it's linked to, not an amount of money. So even if he makes a perfect copy of his TransLink card, he's paying the fare. In fact, the only criminal activity possible on this system would be to hijack someone else's card and ride the trains with their money. Either way, BART gets paid. It's still illegal, though, and requires equipment and expertise far beyond any possible payoff.
As for why Nathan has a TransLink card and account – well, he was trying to impress his environmentalist then-girlfriend by pretending not to own a car and going everywhere by public transit. Unfortunately, the relationship only lasted until a particularly bitter discussion about the human cost of Coltan mining in Africa.