Citadel Read Online Free Page B

privates and corporals
of the German air force, who squeezed into the
other carriages.
    His car half empty and comfortable, he put
himself into a seat. The train sat … and sat … and
sat. Finally a German policeman entered the car
and examined the papers of all, including Basil,
without incident. Yet still the train did not leave.
    Hmm, this was troubling.
    A lesser man might have fumbled into panic.
The mark had noticed his papers missing, called
the police, who had called the German police.
Quickly enough they had put a hold on the train,
fearing that the miscreant would attempt to flee
that way, and now it was just a matter of waiting
for an SS squad to lock up the last of the Jews before
it came for him.
    However, Basil had a sound operational principle
which now served him well. Most bad things
don’t happen. What happens is that in its banal,
boring way, reality bumbles along.
    The worst thing one can do is panic. Panic betrays
more agents than traitors. Panic is the true
enemy.
    At last the train began to move.
    Ah-ha! Right again.
    But at that moment the door flew open and a
late-arriving Luftwaffe colonel came in. He looked
straight at Basil.
    â€œThere he is! There’s the spy!” he said.
    A few days earlier (cont’d)
    â€œA book code,” said Basil. “I thought that was for
Boy Scouts. Lord Baden-Powell would be so
pleased.”
    â€œActually,” said Sir Colin, “it’s a sturdy and almost
impenetrable device, very useful under certain
circumstances, if artfully employed. But
Professor Turing is our expert on codes. Perhaps,
Professor, you’d be able to enlighten Captain St.
Florian.”
    â€œIndeed,” said the young man in the tweeds, revealing
himself by name. “Nowadays we think
we’re all scienced up. We even have machines to do
some of the backbreaking mathematics to it,
speeding the process. Sometimes it works, sometimes
it doesn’t. But the book code is ancient, even
biblical, and that it has lasted so long is good proof
of its applicability in certain instances.”
    â€œI understand, Professor. I am not a child.”
    â€œNot at all, certainly not given your record. But
the basics must be known before we can advance
to the sort of sophisticated mischief upon which
the war may turn.”
    â€œPlease proceed, Professor. Pay no attention to
Captain St. Florian’s abominable manners. We interrupted
him at play in a bawdy house for this
meeting and he is cranky.”
    â€œYes, then. The book code stems from the presumption
that both sender and receiver have access
to the same book. It is therefore usually a
common volume, shall we say Lamb’s Tales from
Shakespeare . I want to send you a message, say
‘Meet me at two p.m. at the square.’ I page through
the book until I find the word ‘meet.’ It is on page
17, paragraph 4, line 2, fifth word. So the first line
in my code is 17-4-2-5. Unless you know the book,
it is meaningless. But you, knowing the book, having
the book, quickly find 17-4-2-5 and encounter
the word ‘meet.’ And on and on. Of course variations
can be worked—we can agree ahead of time,
say, that for the last designation we will always be
value minus two, that is, two integers less. So in
that case the word ‘meet’ would actually be found
at 17-4-2-3. Moreover, in picking a book as decoder,
one would certainly be prone to pick a common
book, one that should excite no excitement,
that one might normally have about.”
    â€œI grasp it, Professor,” said Basil. “But what,
then, if I take your inference, is the point of choosing
as a key book the Right Reverend MacBurney’s The Path to Jesus , of which only one copy exists,
and it is held under lock and key at Cambridge?
And since last I heard, we still control Cambridge.
Why don’t we just go to Cambridge and look at the
damned thing? You don’t need an action-this-day
chap like me for that.