Amsterdam, like New York and San Francisco, is world-renowned as a gathering place for computer enthusiasts, or “hackers.” Although Baumann had been in prison too long to be conversant in the latest technology, he knew where to find someone who was. He contacted a member of the Amsterdam-based Dutch organization Hacktic, which publishes a magazine for computer hackers, and arranged a meeting. He described the sort of person he was looking for: a hacker based in New York, without a criminal past.
“No,” he was told, “you are looking for a cracker-not a hacker. A hacker makes it his mission to understand, shall we say, undocumented technology, so that the government doesn’t enslave us, and to make the world a better place. A cracker has the same skills but uses them, so to speak, to break into your house, often for mercenary purposes.”
“All right, then, a cracker,” Baumann said.
“I have a name for you,” his contact said. “But he will only take on your project, whatever it is, if he finds it of interest-and enormously lucrative.”
“Oh, that he will,” said Baumann. “He will find it both.”
On his second-to-last morning in Amsterdam, he purchased a small device at a large electronics supply house for one thousand guilders, which was then equivalent to six hundred dollars. It was an “ATM Junior,” used by banks to encode magnetic strips on bank and credit cards. With this device he recoded the magnetic strips on each stolen credit card.
When a credit card is used at a retail establishment, it is usually swiped through a transponder, which reads the CVC number at the head of the magnetic stripe and immediately sends it over a telephone line to the credit card company’s central data-processing facility. The computers there check whether the card in question is expired, overextended, or stolen. If it is not, the computers send back an approval code within a second or two. (American Express uses two-digit approval codes, while Visa and MasterCard use four- or five-digit ones.)
Baumann had little doubt that most if not all of these credit cards had already been reported as stolen. If they hadn’t yet, it was simply a matter of time.
But he had circumvented that process. Each credit card now had an approval code of the appropriate number of digits encoded in its magnetic stripe. Whenever a merchant swiped one of these cards through the transponder, the approval code would instantly appear on the transponder’s readout. The machine would read the code-not send it out.
It was highly unlikely the merchant would wonder why the telephone hadn’t dialed, why several seconds hadn’t elapsed before the approval code came in. And if that happened, why, Baumann would remark that the magnetic stripe on the back of the card must have worn out. Too bad. And that would be the end of that. An excellent chance of success, with virtually no risk.
In his remaining time, Baumann ordered several sets of letterhead stationery for several notional, amorphous firms-an import-export company, a law firm, a storage facility.
And he reserved a seat on a Sabena flight from Brussels to London under a false name for which he had no documentation, knowing that, so long as he traveled within the European Commonwealth, he would not be required to show a passport. Then he booked a coach seat from London to New York under the name of one of his newly acquired American passports, that of a businessman and entrepreneur named Thomas Allen Moffatt.
Etienne Charreyron had arranged to use a deserted horse barn on the outskirts of Huy that belonged to a business associate who was in Brussels for the entire month. The associate had recently liquidated all of his family’s livestock at auction.
The barn still smelled strongly of horse manure and damp hay and machine oil. The lighting was barely adequate. In the dim, dank interior, Charreyron opened a battered leather suitcase and gingerly removed three black plastic utility boxes the size of shoeboxes. The lid of each was a plate of brushed aluminum, and on this plate were three tiny bulbs, light-emitting diodes.
“This light tells you that the pocket pager is on and functioning,” Charreyron explained to Baumann. “This one tells you that the battery is emitting power. And this one indicates that the timer is functioning.”
Charreyron slid the aluminum plate off one of the fusing mechanisms. “I’ve set up two separate systems on opposite sides, for redundancy. Two nine-volt batteries, two sets of two screw posts each to connect to the blasting caps. Two timers, two pager-receivers set to the same frequency, two relays. Even two ferrite bars for antennae.” He looked up. “It will beat the bomb-disposal people. Doubles the chances of the thing working, hmm?”
“And one microwave sensor.”
“That’s all there’s room for, and certainly all you’ll need.”
“Shall we test one of them?”
“Yes, of course.” Charreyron lifted one of the black boxes.
“Actually,” Baumann said, grabbing another, “let’s try this one.”
Charreyron smiled slyly, seeming to enjoy the sport. “Whatever you like.”
He brought the box over to an empty fifty-five-gallon steel drum at the far end of the barn and put it on a narrow wooden plank that had been placed across the open top of the barrel. He attached two blasting caps to it, then walked to the other side of the barn.
“First test,” the Belgian said, “is for radio control.”
He took a small cellular phone from his breast pocket, opened it, and dialed a number. As soon as he had done so, he looked at his watch. Baumann did the same.
The two men waited in silence.
Forty-five seconds later the barn echoed with the sound of a gunshot. The blasting caps that dangled from the fusing mechanism had detonated, giving off fragments that were contained by the steel barrel.
“A long delay,” Baumann observed.
“It varies.”
“Yes.” The detonator that set off the blasting caps had been armed by a circuit that closed when the built-in pager received a signal sent by satellite. Depending on how much satellite traffic there was at any given moment, the page signal could be received in a few seconds or a few minutes. “What about the microwave sensor?”
“Certainly.” Charreyron walked across the barn to the steel barrel and attached a fresh set of blasting caps to the fusing mechanism. He rearmed it and pushed a button to activate a time-delay switch.
“As soon as the timer runs down, the microwave sensor is armed. You can set the time delay for as short as ten seconds.”
“And as long as-?”
“Seventy-two hours. But if you need a longer delay, I can easily replace it.”
“No, that’ll do.”
“Good. I’ve set this for ten seconds. And now, the microwave-yes.” From across the dim expanse, Baumann could see a red light wink on. “It’s armed now. Would you like to…?”
“Distance?”
“Twenty-five feet, but that too can be adjusted.”
Baumann walked slowly toward the steel drum, then stopped approximately thirty feet from it. Then he approached step by step, until he was startled by the loud explosion of the blasting caps.
“Very precise,” he said.
“It’s top-quality,” Charreyron said, permitting himself a proud smile.
“You do good work. But what about the signature, as we discussed?”
“That took me quite some time to research. But I came up with a rather convincing Libyan signature.”
Most explosive devices leave “signatures” that permit an investigator to determine who originated them. They might be how the knots are tied, how connections are soldered, how wires are cut.
The Provisional Irish Republican Army, for instance, makes its bomb fuses in lots of a hundred or so. A number of PIRA technicians get together in a warehouse or barn and work without stop for a few days, making identical fuses, which are then parceled out. This has been confirmed both by intelligence and by inspecting the fusing mechanisms of unexploded PIRA bombs: one can tell from the identical, if minuscule, markings that every wire has been cut with the same pair of wirecutters. Some terrorist groups leave a signature unintentionally, out of sloppiness, because they have always constructed a bomb in a certain way. Some, however, do so deliberately, as a subtle way to claim credit.