Cryptography Reference
In-Depth Information
acquired automatically. Of course, this doesn't mean that computers have
already evolved to being able to understand contents, but they can classify
them automatically. One of the most important technologies in this respect
seems to be the N-gram Analysis developed and patented by the NSA. Com-
puters can use this method to quickly sort large quantities (several million)
of messages by author, language, content, writing style, and so on. There is
no longer a programmer at his desk wracking his brain about sorting criteria.
For example, the computer is fed with 100 emails from a range of interesting
topics or circle of authors, and then filters 'suspect' emails all on its own. You
see how naıve it is to believe that intelligence agencies' computers could be
overfed by appending words like 'coke' or 'bomb-building instructions'. The
remarkable thing is how insensitive the N-gram Analysis is to errors: according
to the NSA research workgroup, about 10 % to 15 % of all characters can be
faulty. You can easily imagine where this is important: in writing recognition
for automatic evaluation of telefaxes.
This technique is also doubtful in that it has been commercially available since
1994. Businesses are also highly interested in classifying by contents. I knew
a product (Xtra Secure, www.thunderstore.com ; which didn't use N-gram
Analysis though) that assigned security not only by access privileges, but also
by the contents of files or emails. This means that a trainee wouldn't have
unauthorized access to sensitive data even if the administrator forgot to set his
access privileges right. Or she can read files, but cannot pack them into email
and send them to somebody. This is major progress, but the same technique
can be used to achieve a new quality of corporate internal surveillance.
An Octopus by the Name of Echelon
Yet another sensational heading — and one that has a good reason, because we
are talking of widely proven findings about global interception activities.
The technically most interesting forms of eavesdropping by major Western
intelligence agencies appeared to have arranged themselves in the strictly secret
worldwide espionage network known as the Echelon system . This system
appears to mainly work out of one single gigantic power center — the NSA, as
you might have guessed.
There is quite a lot of information on Echelon on the Internet. One interest-
ing starting point is to launch your favorite search engine to look for +NSA
+UKUSA (in this spelling). Another source of information is looking for 'Ech-
elon' in Wikipedia. It is rewarding. However, a large amount of information
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