“Not really,” Ada said. “The consensus is either that David wasn’t in his right mind when he created it, or that he made it using a one-time pad.”
And as she said it, she lifted from the table the floppy disk Gregory had brought her. She studied it.
It had been years since she had broken an encryption, but she still recognized the buzzing, electric feeling of being on the cusp of undoing one—she had first felt it as a child, with David next to her, guiding her—and it overtook her now. She felt light-headed.
“Do you see it?” said Gregory.
There were fifty-three letters in the encryption.
DHARSNELXRHQHLTWJFOLKTWDURSZJZCMILWFTALVUHVZRDLDEYIXQ
There were fifty-three letters in the message David had written to her, on the label carefully affixed to the original disk:
Dear Ada. A puzzle for you. With my love, your father, David Sibelius.
So there it was, at last: the one-time pad that Hayato had guessed might exist. Without the original disk, without the label stuck to it, the copies they had all been working from were meaningless. The encryption, without its key, was an orphan.
From there, it took them ten minutes to decrypt the rest. Gregory’s eggs arrived. He let them go cold.
“Everything okay?” asked the puzzled waitress, but they barely looked up.
They assigned each letter in the encryption its logical number—4 for D, 8 for H, 1 for A, 18 for R, 19 for S, 14 for N—and from each subtracted the numerical substitute for the letters in the message on the label: 4 for D, 5 for E, 1 for A, 18 for R, 1 for A, 4 for D.
4 minus 4 was 0.
8 minus 5 was 3.
1 minus 1 was 0.
18 minus 18 was 0.
19 minus 1 was 18.
14 minus 4 was 10.
0, 3, 0, 0, 18, 10 translated to nothing obvious at first: it looked something like C _ R J.
“Try shifting every letter up to the next one,” said Ada. And _C_ _ R J suddenly became ADAASK.
They continued to work until, at last, the whole decrypted message sat before them on the screen, unpunctuated and abrupt, a telegraph message sent to them from twenty-six years in the past.
ADA ASK ELIXIR WHO IS HAROLD WITH LOVE YOUR FATHER HAROLD CANADY
It was easy to reach Frank Halbert, now the head of the old laboratory at the Bit. His information was public, and they found it quickly online. He answered Ada’s e-mail immediately. Yes, he said; the program’s still running.
1980s
Boston
Liston was waiting for her in the hallway outside David’s room at St. Andrew’s. Ada kept one hand in her jacket pocket, around the four-leaf clover charm she had taken out of David’s grip. Would he miss it, when he woke? Inside it, the key rattled gently.
When they reached Savin Hill, Ada said there was something she needed from inside David’s house, and Liston, kindly, left her alone. She entered through the kitchen, walked into David’s office. And then she moved directly to the filing cabinet that she had tried in vain to open the first time she ever searched the house.
The tall tan cabinet still had its crooked look from when she had tried to force it open with a crowbar. Now, holding her breath, she fitted the silver key neatly into the lock. It turned.
She paused before pulling open the top drawer. She was relieved to find it empty.
The second drawer, however, was nearly full to the brim with a stack of pages printed on a dot-matrix printer, every page still connected to its neighbor, every perforated edge still attached. She lifted the stack out of the drawer.
The Unseen World, the first page said, in larger font across the top. She paused: it was the same title David had given to the document that Gregory had found on his computer, which she had not yet made sense of.
Below it: pages and pages of code. A hundred printed pages. Maybe more. It was written in an iteration of Lisp, and it looked like a game; she could see that; she recognized its cues and commands, its particular shape. As for what it was meant to do: that was beyond her. And she did not know on what platform it could be run.
Was this, she wondered, what David had been working on, secretly, in his final years in the house? All those evenings he had disappeared into his office; all those mornings she had woken him up after he had fallen asleep, the night before, at his desk?
She reassembled the pages. She placed them on his desk, and then turned on his computer.
Already she had been through every file he’d saved, and she had seen nothing like this document. Still, she searched again, and then once more, looking for anything that resembled The Unseen World in electronic form.
She found nothing.
She’d have to manually type every line of the printed text herself, then—slowly and painstakingly, avoiding mistakes that might corrupt the program. Only once she had an electronic copy could she begin to determine the platform it required.
That evening, she began.
(define flip
#decl (process)
(cond ((type? , rep subr fsubr) (set read-table (put (ivector 3444 0) (chtype (ascii i \() fix) i \)) (evaltype form segment) (applytype grrt fix) (put (alltypes) 3 (4 (alltypes))) (substitute 2 1)
(off .bh))))
(indec (ff) string) (define ilo (body type np1 np2 “optional” m1 m2) #indec ((body np1 np2 p1 p2) string (type) fix) (cond ((or (and (member “(open drawer)” .body) (not (member ,nbup ,winners))) (and (member .np1 ,winners))) (member ,ff .body))) (eval (parse .body))))) (dismiss t))
\
; “subtitle kitchen, shawmut way”
(define house () (cond ((verb? “search”) (say)
2009
Boston
There was a seat available on the same plane to Boston that Gregory was taking. It was leaving the next day.
After meeting with Gregory, Ada didn’t go back to Tri-Tech. She couldn’t. She would find out from Tom, who would find out from Bill, how the meeting had gone. She would call in the next day and tell Bill that she had to go to Boston. “Family emergency,” she would say—and, because he had never once asked her anything about her life, because he had no sense that, in fact, she had no family, he wouldn’t know any different. In a way, she told herself, it was true.
She would quit, she decided. She had to. But all of that could wait until her return.
That night, at home, she turned in a full circle, assessing what to pack. She couldn’t think well. She mouthed the names of items as she put them into her suitcase. It was winter. January. That year, San Francisco was cold, but Boston would be freezing. She opened the bottom drawer of her dresser, rifled through the clothing in her closet. Since moving to the West Coast, she had shed most of her cold-weather gear. She remembered Boston’s version of winter as something breathtaking, unkind.
She was certain she was forgetting something. At 6:45 the following morning, she left for the airport anyway, in a taxi whose driver sang along lowly to the songs on the radio. She would meet Gregory there.