Cryptography Reference
In-Depth Information
signing and separate use later on in less secure landscapes. Keys can be
sent to key servers or fetched from them directly from within GnuPG.
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Similarly to PGP 5.0 and successors, GnuPG can be embedded in mailers
and graphic user interfaces. This is important for the program's accep-
tance. A uniform graphic interface (GPA) has been worked on for several
years, but is still unsatisfactory.
However, I constantly quarrel with the program. Its installation and first-time
use simply overtax inexperienced users. It certainly overtaxed me when I tried
to test GnuPG 2.0 under time pressure: I was supposed to download four
additional libraries from the GnuPG homepage, then compile and install them,
or the program wouldn't run. Well, who has that time to waste other than
somebody who likes to play with the program?
There is a tutorial, plus there are FAQs, a long user manual, and an exten-
sive ManPage under UNIX. But the tutorial goes into lengths describing the
background of email security as well as asymmetric and symmetric encryption
before it deals with commands. When you finally make it to that part, however,
you won't be able to use it, because you'll first have to create a key. Even the
mini How-To (still in its 1999 edition) is not much better; it is designed for
experienced Linux administrators rather than for the average user. And it is the
average user, after all, who is supposed to use GnuPG for mail encryption on
their household computers!
All in all, there are many small tripwires that can unnerve users as they try
to get things done with the program. For example, it is almost impossible to
find out what symmetric method is actually used, and how the configuration
file is to be expanded. The ManPage of GnuPG 1.4.5 lists almost 300 optional
switches for calling the program in alphabetic order. Which ones are the most
important? All right, GnuPG is conceived as a plug-in for mailers, but mailers
use only a tiny part of its capabilities.
Another critical point is that it accepts lousy passwords, like passwords only
a single letter long. Though improvement had been promised, Release 1.4.5 is
still as 'tolerant' as ever.
There is a conflict I'm particularly interested in: Alice has GnuPG 1.0.4, which
supports AES, installed, and sends Bob an encrypted email. Since Bob uses
GnuPG 1.0.3, which doesn't talk AES, he cannot decrypt the message. Now
what? With SSH (see Section 7.3), the server and the client could negotiate the
algorithm they want to use, but that doesn't work for mail! There is a solution:
