The advantages of this were twofold. It would be nearly impossible for an outside listener to decode the digital messages without the proper encryption/decryption algorithm. But more importantly, the sound of feeding krill occurred naturally in the waters under the ice pack. If an acoustic surveillance sensor happened to intercept a transmission, the sound would be classified as typical ambient noise made by local sea life. No sensor operator or acoustic analyst in the world would recognize it as a manmade communications signal. For all practical purposes, that made the system invisible to anyone who did not already know of its existence.
The encryption/decryption algorithm at the heart of this covert transponder system had been programmed by a pair of graduate students from the Massachusetts Institute of Technology. Perhaps one or both of the students had eventually grown to suspect that their enigmatic employer did not really represent an eco-friendly alternative energy firm, as he had claimed. Perhaps the young programmers had also guessed that the true purpose of the software had nothing to do with bio-density surveys. But any misgivings the two students might have felt were now moot. Both men had been killed within hours of delivering the final version of their software.
Detectives from the Cambridge Police Department were investigating both deaths, but had failed to turn up evidence of a connection between the cases. One of the students had slipped in a hotel shower and cracked his skull. The other had been killed by a hit-and-run driver. The circumstances of the cases were quite different, and both deaths appeared to be accidental. Even so, the police found it exceedingly suspicious that two students from the same department at MIT had died on the same afternoon.
At various points in the investigation, the homicide detectives considered and discarded a long list of possible suspects, including friends of the victims, fellow students, known enemies, relatives, girlfriends, possible romantic rivals, and several smalltime drug dealers known to ply their wares near the MIT campus.
The drug angle was a stretch. Neither of the victims were known users, and the toxicology screens from their autopsies showed no traces of any controlled substances. The dealers had been added to the list when the detectives realized that they’d run out of suspects. With two college-age men dead under suspicious circumstances, it was possible that drugs were somehow involved, and no one seemed to have any alternative leads.
But the suspicions of the police — whatever they might have been — did not involve trained assassins from the Chinese military, nor covert under-ice communications systems, nor hijacked Russian nuclear submarines. Which meant that the Cambridge police had no chance of actually figuring out who had murdered their two students, or why.
A little over 4,600 nautical miles northwest of Cambridge, Massachusetts, the motive for the MIT murders was gliding quietly through the frigid waters beneath the Siberian ice pack. Submarine K-506 had been built as part of the Soviet Union’s Project 667BDR construction program: the
Although the submarine was more than three decades old, and much noisier than current generations of missile subs, it was still quiet enough to escape detection at low speeds. So it moved slowly and deliberately, creeping through the dark waters under the ice at less than four kilometers per hour — just enough speed to keep water moving across the rudders and stern planes, for steering and depth control.
At a range of one kilometer from the designated coordinates, the submarine’s
The signal was received by the cylindrical titanium transducer. Thin wafers of piezoelectric crystal within the transducer resonated in time with the vibrations of the sound waves. The tiny stresses created by these vibrations caused the crystal wafers to alternately contract and expand. The fluctuations were nearly microscopic in scale, but each deformation of the piezoelectric crystals generated a minute pulse of electricity.
The technology had been invented for quartz movement wristwatches, but it worked equally well in this application. Each electrical pulse was channeled into a transistor, where it was amplified for better examination. The amplified pulses were then routed to a binary discriminator circuit, where they were converted to digital ones, or digital zeroes, depending upon their strength and polarity.
The stream of digital pulses from the discriminator circuit passed through a splitter bus, and then a short length of ribbon cable, to reach a microprocessor configured as a binary parser.
The parser stripped out ambient ocean sounds and the masking junk information that had been woven into the acoustic signal to disguise it as random biological noise. The output of the parser was a complete and coherent digital message, rendered in perfectly-legible binary code.
The digital message shot up the fiber-optic wires at the core of the Kevlar cable, and followed the cable through the thick ice layer, to another microprocessor, sheltered in an insulated protective housing under a few centimeters of concealing ice and snow.
The second microprocessor examined the contents of the digital signal, to determine whether or not it contained a
No destruct signal was present, and the explosives were not triggered.
The microprocessor reverted to its secondary program, encrypting the digital signal to protect its contents. When the encryption process was complete, the computer immediate re-encrypted the signal, using an entirely different code scheme. The double-encrypted block of digital code was uploaded to the outgoing message queue of a satellite phone within the same insulated enclosure.
On command, the phone dialed a pre-programmed telephone number, accessing a commercial communications satellite network. When the connection protocols were synchronized, the hidden telephone unit transmitted its waiting message to a ComStar IV series satellite in standard commercial orbit.
The satellite phone account was legitimate, one of many commercial accounts opened for this specific purpose. The registered account owner was a dummy corporation in Spain, again one of many established solely for this operation. But the bills were paid on time, and the account had never been flagged for suspected misconduct.
Other than an automated notation to charge the call against the user’s account, no human or machine in the telecommunications industry paid any attention whatsoever to the call. It was a routine commercial transaction. The message from K-506 joined the flow of ordinary daily phone traffic, and no one was any the wiser.
When the call was completed, the satellite phone kept the connection open, and transmitted the access code for its voicemail box. There was one waiting message, which the satellite phone downloaded, before terminating the call.
The incoming message was double encrypted in the same manner that the outgoing message had been. It was routed from the phone’s message queue to the adjoining microprocessor, which unraveled both layers of encryption, before shooting it back down the Kevlar cable toward the hanging titanium cylinder.
The process continued in reverse, and ended when the transducer injected a stream of white noise into the water, 100 meters below the ice. The transmission sounded a great deal like the ordinary noises of feeding krill, and not at all like tactical instructions to a nuclear missile submarine.
A kilometer away the K-506 received its updated orders. With slow but deliberate speed, the submarine turned and began to move north.
CHAPTER 35
National Security Advisor Gregory Brenthoven walked into the empty room. The high-backed leather chairs were all pushed against the long mahogany table. The air was still, and quiet.
