Digital Fortress

by Dan Brown

  Technicians were rushing everywhere.

  Something in Susan told her they were close. "We can do this!" she declared, taking control. "Of all the differences between uranium and plutonium, I bet only one can be represented as a prime number! That's our final clue. The number we're looking for is prime!"

  Jabba eyed the uranium/plutonium chart on the monitor and threw up his arms. "There must be a hundred entries here! There's no way we can subtract them all and check for primes."

  "A lot of the entries are nonnumeric," Susan encouraged. "We can ignore them. Uranium's natural, plutonium's man-made. Uranium uses a gun barrel detonator, plutonium uses implosion. They're not numbers, so they're irrelevant!"

  "Do it," Fontaine ordered. On the VR, the final wall was eggshell thin.

  Jabba mopped his brow. "All right, here goes nothing. Start subtracting. I'll take the top quarter. Susan, you've got the middle. Everybody else split up the rest. We're looking for a prime difference."

  Within seconds, it was clear they'd never make it. The numbers were enormous, and in many cases the units didn't match up.

  "It's apples and goddamn oranges," Jabba said. "We've got gamma rays against electromagnetic pulse. Fissionable against unfissionable. Some is pure. Some is percentage. It's a mess!"

  "It's got to be here," Susan said firmly. "We've got to think. There's some difference between plutonium and uranium that we're missing! Something simple!"

  "Ah… guys?" Soshi said. She'd created a second document window and was perusing the rest of the Outlaw Labs document.

  "What is it?" Fontaine demanded. "Find something?"

  "Um, sort of." She sounded uneasy. "You know how I told you the Nagasaki bomb was a plutonium bomb?"

  "Yeah," they all replied in unison.

  "Well…" Soshi took a deep breath. "Looks like I made a mistake."

  "What!" Jabba choked. "We've been looking for the wrong thing?"

  Soshi pointed to the screen. They huddled around and read the text: …the common misconception that the Nagasaki bomb was a plutonium bomb. In fact, the device employed uranium, like its sister bomb in Hiroshima.

  * * *

  "But-" Susan gasped. "If both elements were uranium, how are we supposed to find the difference between the two?"

  "Maybe Tankado made a mistake," Fontaine ventured. "Maybe he didn't know the bombs were the same."

  "No." Susan sighed. "He was a cripple because of those bombs. He'd know the facts cold."

  Chapter 126

  "One minute!"

  Jabba eyed the VR. "PEM authorization's going fast. Last line of defense. And there's a crowd at the door."

  "Focus!" Fontaine commanded.

  Soshi sat in front of the Web browser and read aloud. …Nagasaki bomb did not use plutonium but rather an artificially manufactured, neutron-saturated isotope of uranium 238."

  "Damn!" Brinkerhoff swore. "Both bombs used uranium. The elements responsible for Hiroshima and Nagasaki were both uranium. There is no difference!"

  "We're dead," Midge moaned.

  "Wait," Susan said. "Read that last part again!"

  Soshi repeated the text. "…artificially manufactured, neutron-saturated isotope of uranium 238."

  "238?" Susan exclaimed. "Didn't we just see something that said Hiroshima's bomb used some other isotope of uranium?"

  They all exchanged puzzled glances. Soshi frantically scrolled backward and found the spot. "Yes! It says here that the Hiroshima bomb used a different isotope of uranium!"

  Midge gasped in amazement. "They're both uranium-but they're different kinds!"

  "Both uranium?" Jabba muscled in and stared at the terminal. "Apples and apples! Perfect!"

  "How are the two isotopes different?" Fontaine demanded. "It's got to be something basic."

  Soshi scrolled through the document. "Hold on… looking… okay…"

  "Forty-five seconds!" a voice called out.

  Susan looked up. The final shield was almost invisible now.

  "Here it is!" Soshi exclaimed.

  "Read it!" Jabba was sweating. "What's the difference! There must be some difference between the two!"

  "Yes!" Soshi pointed to her monitor. "Look!"

  They all read the text: …two bombs employed two different fuels… precisely identical chemical characteristics. No ordinary chemical extraction can separate the two isotopes. They are, with the exception of minute differences in weight, perfectly identical.

  "Atomic weight!" Jabba said, excitedly. "That's it! The only difference is their weights! That's the key! Give me their weights! We'll subtract them!"

  "Hold on," Soshi said, scrolling ahead. "Almost there! Yes!" Everyone scanned the text. …difference in weight very slight… …gaseous diffusion to separate them… …10,032498X10?134 as compared to 19,39484X10?23.** "There they are!" Jabba screamed. "That's it! Those are the weights!"

  "Thirty seconds!"

  "Go," Fontaine whispered. "Subtract them. Quickly."

  Jabba palmed his calculator and started entering numbers.

  "What's the asterisk?" Susan demanded. "There's an asterisk after the figures!"

  Jabba ignored her. He was already working his calculator keys furiously.

  "Careful!" Soshi urged. "We need an exact figure."

  "The asterisk," Susan repeated. "There's a footnote."

  Soshi clicked to the bottom of the paragraph.

  Susan read the asterisked footnote. She went white. "Oh… dear God."

  Jabba looked up. "What?"

  They all leaned in, and there was a communal sigh of defeat. The tiny footnote read: **12% margin of error. Published figures vary from lab to lab.

  Chapter 127

  There was a sudden and reverent silence among the group on the podium. It was as if they were watching an eclipse or volcanic eruption-an incredible chain of events over which they had no control. Time seemed to slow to a crawl.

  "We're losing it!" a technician cried. "Tie-ins! All lines!"

  On the far-left screen, David and Agents Smith and Coliander stared blankly into their camera. On the VR, the final fire wall was only a sliver. A mass of blackness surrounded it, hundreds of lines waiting to tie in. To the right of that was Tankado. The stilted clips of his final moments ran by in an endless loop. The look of desperation-fingers stretched outward, the ring glistening in the sun.

  Susan watched the clip as it went in and out of focus. She stared at Tankado's eyes-they seemed filled with regret. He never wanted it to go this far, she told herself. He wanted to save us. And yet, over and over, Tankado held his fingers outward, forcing the ring in front of people's eyes. He was trying to speak but could not. He just kept thrusting his fingers forward.

  In Seville, Becker's mind still turned it over and over. He mumbled to himself, "What did they say those two isotopes were? U238 and U…?" He sighed heavily-it didn't matter. He was a language teacher, not a physicist.

  "Incoming lines preparing to authenticate!"

  "Jesus!" Jabba bellowed in frustration. "How do the damn isotopes differ? Nobody knows how the hell they're different?!" There was no response. The room full of technicians stood helplessly watching the VR. Jabba spun back to the monitor and threw up his arms. "Where's a nuclear fucking physicist when you need one!"

  * * *

  Susan stared up at the QuickTime clip on the wall screen and knew it was over. In slow motion, she watched Tankado dying over and over. He was trying to speak, choking on his words, holding out his deformed hand… trying to communicate something. He was trying to save the databank, Susan told herself. But we'll never know how.

  "Company at the door!"

  Jabba stared at the screen. "Here we go!" Sweat poured down his face.

  On the center screen, the final wisp of the last firewall had all but disappeared. The black mass of lines surrounding the core was opaque and pulsating. Midge turned away. Fontaine stood rigid, eyes front. Brinkerhoff looked like he was about to get sick.

  "Ten seconds
!"

  Susan's eyes never left Tankado's image. The desperation. The regret. His hand reached out, over and over, ring glistening, deformed fingers arched crookedly in stranger's faces. He's telling them something. What is it?

  On the screen overhead, David looked deep in thought. "Difference," he kept muttering to himself. "Difference between U238 and U235. It's got to be something simple."

  A technician began the countdown. "Five! Four! Three!"

  The word made it to Spain in just under a tenth of a second. Three… three.

  It was as if David Becker had been hit by the stun gun all over again. His world slowed to stop. Three… three… three. 238 minus 235! The difference is three! In slow motion, he reached for the microphone…

  At that very instant, Susan was staring at Tankado's outstretched hand. Suddenly, she saw past the ring… past the engraved gold to the flesh beneath… to his fingers. Three fingers. It was not the ring at all. It was the flesh. Tankado was not telling them, he was showing them. He was telling his secret, revealing the kill-code-begging someone to understand… praying his secret would find its way to the NSA in time.

  "Three," Susan whispered, stunned.

  "Three!" Becker yelled from Spain.

  But in the chaos, no one seemed to hear.

  "We're down!" a technician yelled.

  The VR began flashing wildly as the core succumbed to a deluge. Sirens erupted overhead.

  "Outbound data!"

  "High-speed tie-ins in all sectors!"

  Susan moved as if through a dream. She spun toward Jabba's keyboard. As she turned, her gaze fixed on her fiance, David Becker. Again his voice exploded overhead.

  "Three! The difference between 235 and 238 is three!"

  Everyone in the room looked up.

  "Three!" Susan shouted over the deafening cacophony of sirens and technicians. She pointed to the screen. All eyes followed, to Tankado's hand, outstretched, three fingers waving desperately in the Sevillian sun.

  Jabba went rigid. "Oh my God!" He suddenly realized the crippled genius had been giving them the answer all the time.

  "Three's prime!" Soshi blurted. "Three's a prime number!"

  Fontaine looked dazed. "Can it be that simple?"

  "Outbound data!" a technician cried. "It's going fast!"

  Everyone on the podium dove for the terminal at the same instant-a mass of outstretched hands. But through the crowd, Susan, like a shortstop stabbing a line drive, connected with her target. She typed the number 3. Everyone wheeled to the wall screen. Above the chaos, it simply read.

  ENTER PASS-KEY? 3

  "Yes!" Fontaine commanded. "Do it now!"

  Susan held her breath and lowered her finger on the ENTER key. The computer beeped once.

  Nobody moved.

  Three agonizing seconds later, nothing had happened.

  The sirens kept going. Five seconds. Six seconds.

  "Outbound data!"

  "No change!"

  Suddenly Midge began pointing wildly to the screen above. "Look!"

  On it, a message had materialized.

  KILL CODE CONFIRMED.

  "Upload the firewalls!" Jabba ordered.

  But Soshi was a step ahead of him. She had already sent the command.

  "Outbound interrupt!" a technician yelled.

  "Tie-ins severed!"

  On the VR overhead, the first of the five firewalls began reappearing. The black lines attacking the core were instantly severed.

  "Reinstating!" Jabba cried. "The damn thing's reinstating!"

  There was a moment of tentative disbelief, as if at any instant, everything would fall apart. But then the second firewall began reappearing… and then the third. Moments later the entire series of filters reappeared. The databank was secure.

  The room erupted. Pandemonium. Technicians hugged, tossing computer printouts in the air in celebration. Sirens wound down. Brinkerhoff grabbed Midge and held on. Soshi burst into tears.

  "Jabba," Fontaine demanded. "How much did they get?"

  "Very little," Jabba said, studying his monitor. "Very little. And nothing complete."

  Fontaine nodded slowly, a wry smile forming in the corner of his mouth. He looked around for Susan Fletcher, but she was already walking toward the front of the room. On the wall before her, David Becker's face filled the screen.

  "David?"

  "Hey, gorgeous." He smiled.

  "Come home," she said. "Come home, right now."

  "Meet you at Stone Manor?" he asked.

  She nodded, the tears welling. "Deal."

  "Agent Smith?" Fontaine called.

  Smith appeared onscreen behind Becker. "Yes, sir?"

  "It appears Mr. Becker has a date. Could you see that he gets home immediately?"

  Smith nodded. "Our jet's in Malaga." He patted Becker on the back. "You're in for a treat, Professor. Ever flown in a Learjet 60?"

  Becker chuckled. "Not since yesterday."

  Chapter 128

  When Susan awoke, the sun was shining. the soft rays sifted through the curtains and filtered across her goosedown feather bed. She reached for David. Am I dreaming? Her body remained motionless, spent, still dizzy from the night before.

  "David?" She moaned.

  There was no reply. She opened her eyes, her skin still tingling. The mattress on the other side of the bed was cold. David was gone.

  I'm dreaming, Susan thought. She sat up. The room was Victorian, all lace and antiques-Stone Manor's finest suite. Her overnight bag was in the middle of the hardwood floor… her lingerie on a Queen Anne chair beside the bed.

  Had David really arrived? She had memories-his body against hers, his waking her with soft kisses. Had she dreamed it all? She turned to the bedside table. There was an empty bottle of champagne, two glasses… and a note.

  Rubbing the sleep from her eyes, Susan drew the comforter around her naked body and read the message.

  Dearest Susan,

  I love you.

  Without wax, David.

  She beamed and pulled the note to her chest. It was David, all right. Without wax… it was the one code she had yet to break.

  Something stirred in the corner, and Susan looked up. On a plush divan, basking in the morning sun, wrapped in thick bathrobe, David Becker sat quietly watching her. She reached out, beckoning him to come to her.

  "Without wax?" she cooed, taking him in her arms.

  "Without wax." He smiled.

  She kissed him deeply. "Tell me what it means."

  "No chance." He laughed. "A couple needs secrets-it keeps things interesting."

  Susan smiled coyly. "Any more interesting than last night and I'll never walk again."

  David took her in his arms. He felt weightless. He had almost died yesterday, and yet here he was, as alive as he had ever felt in his life.

  Susan lay with her head on his chest, listening to the beat of his heart. She couldn't believe that she had thought he was gone forever.

  "David." She sighed, eyeing the note beside the table. "Tell me about 'without wax.' You know I hate codes I can't break."

  David was silent.

  "Tell me." Susan pouted. "Or you'll never have me again."

  "Liar."

  Susan hit him with a pillow. "Tell me! Now!"

  But David knew he would never tell. The secret behind "without wax" was too sweet. Its origins were ancient. During the Renaissance, Spanish sculptors who made mistakes while carving expensive marble often patched their flaws with cera-"wax." A statue that had no flaws and required no patching was hailed as a "sculpture sincera" or a "sculpture without wax." The phrase eventually came to mean anything honest or true. The English word "sincere" evolved from the Spanish sincera-"without wax." David's secret code was no great mystery-he was simply signing his letters "Sincerely." Somehow he suspected Susan would not be amused.