Auszug aus Historie COMSEC
The general attitude of this Agency is that no deliberate transmission is free from the possibility
of hostile interception. The thought is that there is really a contradiction in terms of the notion of
an uninterceptible transmission: for. if there were such, the intended recipient. your own distant
receiver. could not pick it up.
Despite all of this. it is clear that some transmissions are considerably more difficult and costly
to intercept than others and some of them carrying information of low intelligence value may not be
worth that cost to the potential hostile interceptor. These factors have a lot to do with the priorities
we establish for providing cryptosystems to various kinds ofcommunications entities.
But. in the case of voice. which is our subject. it has Dot been any rationale of non-interceptibility
which has slowed us down. it is the set of terrifically difficult technical barriers in the way of
lletting such equipment in light, cheap, efficient, secure form, either for strategic high-level links.
as in the case of all the ciphony equipments I've mentioned so far, or for tactical circuits that we
will. in due course. cover.
Still. with the advent of the KY-ll. it appeared that we had at least one part of the ciphony
problem relatively well in hand: that was for fixed-plant, short-range operations where plenty of
bandwidth was available for transmission. These fixed-plant. wjde-band equipments-all of themnot
only could provide secure good quality voice, but had enough room to permit the encryption of
'" several channels of voice with the same key generator. But just as in t.h,..e",case of teletypewriter secu- .- .. ~.~-
rity devices. there was a need to move ciphony equipment out of the cryPloc;en,tfU and nearer to the
environment where the actual user could have more ready access. In the case of the teletypewriter
encryption systems. you will recall. the move was into the communications center where all the
ancillary devices and communications terminal equipment and punched message tapes and message
forms were readily available. In the case of ciphony, the real user was the individual who picks
up the handset and talks-not some professional cryptographer or communicator-but people like
you and me and generals and admirals and presidents. So the next need we faced was to provide an
equipment which could be remote from both cryptocenter and communications center. and used
right in the offices where the actual business of government and strategic military affairs is conducted.
This called for machinery that was smaller and packaged differently than any of the ciphony
equipment we have talked about thus far. SIGSALLY you remember. weighed 55 tons: the next
system weighed a lot less but still needed 6 bays of equipment. The KY-ll was smaller still.
amounting to a couple of rac;ks of equipment configured for communications center use. None of
them were at all suitable for installation in somebody's office.
The resultant product was called the TSEC/KY-l. The most striking feature it had. in contrast
to its predecessor ciphony devices. was that it was neatly packaged in a single cabinet about twothirds
as tall and somewhat fatter than an ordinary safe. Because it was built not to be in a cryptocenter
or a classified communications center where there are guards and controls on access to
prevent theft of equipment and their supporting materials. this KY-l cabinet was in fact a threecombination
safe that contained the whole key generator. the power supply. the digitalizing voice
preparation components-everything except the handset which sits on top.
So. for the first time since World War II with the SIGNIN. we found ours