Cryptography Reference
In-Depth Information
this case, you might guess, is secret sharing. Only a certain group of people in
joint action would be able to activate warheads. This is certainly not a matter
of a simple 'three out of five' scheme.
It is probably clear to you as it is to me: if cryptological work is done to
perfection, then this is an extremely sensitive area. Another fascinating detail
shows how far this can go: of course, all nuclear warheads are optimally pro-
tected against espionage and sabotage. An attempt to get unauthorized hold of
the nuclear charge or the electronics causes the immediate destruction of the
warhead. Gas bottles are used to deform and chemically change the plutonium
body, targeted demolition charges destroy neutron boosters, tritium charges,
and the secret code, of course. After tests showed that 1-mm chip fragments
survived the protective detonation, the software was rewritten so that, based on
secret splitting, all key material was stored as two separate components, which
were kept at addresses more than 1 mm apart on the chip surface.
All these security measures have been successful to date. Not a single warhead
has been reported stolen, nobody has spied out
and
used the universal key,
to public knowledge. With this background, James Bond movies appear even
more absurd, but this is what makes them so attractive.
You surely wonder where such interesting information can be found. I neither
interviewed militaries nor national intelligence agents; I just read the fascinating
article [AndKuhn.tamp] that formed the background for Section 4.4.5. You can
find it on our Web site.
6.3 Digital Signatures
Currently the most popular cryptographic protocol in German politics and
jurisdiction is the
digital signature
. In line with the increasing migration of
information flows to electronic media, it has simply become a necessity to
develop an electronic equivalent for traditional signatures. This is not a prob-
lem cryptologists couldn't handle, but it is a double-edged sword with regard
to law and risk. However, before we can create and study signatures, we have
to deal with
one-way hash functions
.
6.3.1 One-Way Hash Functions
Common hash functions are something IT experts have long been familiar with;
they represent a simple and genial idea. Imagine the following situation: you
create a large database with customer names. The company is doing well, so
