“It has to be in the programming,” they agreed at last, and dismally sat down to tabulate the likeliest ways in which a logjam could have arisen. Every attempt to come up with an alternative possibility proved fruitless; they returned time and again to the one Desmond had originally defined—an unpredictable clash between at least two and conceivably several instructions which the machines interpreted as referring to contradictory or even perhaps nonexistent programmes.
All the time the TV cameras wove back and forth, spying on them.
“I’m exhausted,” Molesey finally announced. “And so are the rest of you, right?” He stretched as he rose from his chair. “I recommend we sleep on it and see if we have any new ideas in the morning.”
“Ah . . .” Desmond intervened. “There are only four bunks in the room next door, you know.”
Molesey started. “No, I didn’t know! What do the idiots expect us to do—use the floor?”
As though answering a cue, Dilys Prinkett came in, yawning, her clothes crumpled, not looking particularly refreshed by her rest.
“Say, you lot must be beat by now,” she said. “Bill is still snoring his head off, but if you want to take over the bunk I was using, one of you . . . Any progress?”
“None at all.”
“Think there’s anything that can be done?”
“Not until we have something to match the encrypted material with.”
“Good, that makes us a unanimous majority. Dr Molesey, I overheard Sir Andrew saying to that awful Finbow woman that he’s left numbers where he can always be reached at the switchboard here. Suppose you call him up and say we want to go home?”
“I’ll do that!” Molesey said, and headed for the phone. After a couple of minutes’ fruitless argument he slammed it back on its hook.
“He left numbers where he can be reached, okay! But he also left orders that he mustn’t be disturbed unless we fix the trouble!”
“I’ll be damned!” Crabtree said, speaking for them all. A moment elapsed in silence full of suppressed fury.
“Look—uh . . .” Desmond spoke up. “I’m not feeling sleepy yet. And Dilys has had at least some rest. Why don’t you three use the bunks that are vacant? I’ll take over Bill’s when he wakes up.”
“Well, if you’re sure—?” Molesey said, brightening.
“Yes, go ahead; I’m quite okay.”
Desmond was no longer okay an hour later. For a while he and Dilys talked desultorily, mostly about working for the Post Office Telecommunications Centre, which had been one of the options open to him when he left university. He asked what conditions were like in the Civil Service.
“Frankly,” she answered with a scowl,* “I think you made the right choice. I don’t know which makes it worse, the fact that the whole setup is paranoid or that the people in charge are as hidebound as a family bible!”
“Uh . . .” He pointed discreetly at the nearer of the TV cameras.
“What are you on about—? Oh, those things! Don’t worry. They’re very unlikely to play over the tape.”
“Tape?”
“Sure, those monitors are on automatic overnight. They aren’t primarily intended as a bugging system, at least not in the conventional sense. The people who designed this place were worried in case some super-subtle brain-bending gas might find its way through the air-conditioners, so they rigged these cameras everywhere to make sure medical personnel could spot the very first signs of aberrant behaviour among the lucky survivors. Christ, it’s a lunatic world we live in anyway, isn’t it? And after the big smash it would be even crazier, so I honestly don’t know how they hope to tell the normal from the abnormal. When you meet some of the power-hungry maniacs I’ve run across. . .”
The words dissolved into a yawn. “Sorry, I’m a lot less rested than I thought I was.”
“You sound very embittered,” Desmond ventured.
“Should I not be? Megalomania is kind of an occupational disease among politicians, and sometimes I suspect they suffer from even worse afflictions.”
She yawned again, immensely wide, and her eyelids drifted shut and she twisted around on her chair and in another few moments was fast asleep.
Left to his own devices, Desmond slipped off his shoes because his feet were getting sore, and set to pacing restlessly back and forth around the room. He knew it would be wise to try and sleep even if he had to make do with some cushions and a patch of floor. But something was preventing him. Something was hovering at the edge of his mind like the ghost of an itch. At last he stopped in his tracks, folded his fingers into fists, and compelled himself to concentrate.
At first it was like trying to trap the images of a dream. But by dint of pure determination he finally nailed down the crucial clue.
Oh, surely they can’t have overlooked that possibility? Or—or could they? It didn’t come up during our discussion!
He had managed to recapture a down-column news item, not from a professional journal but from an ordinary paper, which he had noticed . . . how long ago? A year, two years? Never mind! The point was this. An American bank had run into precisely this sort of trouble; a tiny oversight had rendered their computer facilities unusable. That case too had involved a cypher. How exactly had it happened?
Shutting his eyes, he forced half-forgotten details back to awareness. This bank—that’s it!—protected its customers’ financial records by encrypting them in a manner similar to but less elaborate than the one in use here. And the cypher was changed at intervals of about one hundred days. And the time came when on a date that seemed entirely random the computers refused to part with any of their stored data.
After hours of fruitless struggle the engineers quit for the night, and when they returned everything functioned perfectly.
Then, and only then, they figured out what had gone wrong. The machines had been instructed to discontinue the outgoing cypher as of Day 200, and start with the replacement on Day 201
