The official download site is: GnuPG Homepage. At that location you will find links to mirror sites.
Due to legal restrictions it is not allowed to download GnuPG from servers based in the USA. The USA imposes export restrictions on the export of cryptographic software. This is why PGP is always available in an international and a national (for the USA) version. For the international version the source code has been exported in a printed format as a book. In Europe (Oslo) it has been scanned. More information on that can be found on International PGP Homepage. The international version of PGP is free to be imported into the United States as long as it is not reexported again.
If you already have an installed version of GnuPG or PGP, you should check the signature of the file (see Signatures).
You can obtain GnuPG as a Debian Package, as a RPM package (Redhat Package Manager) or in source code. GnuPG is included in the latest Fedora/Redhat Linux distributions. To check if you have GnuPG installed on your system, use:
rpm -q gnupg
The packages are installed as binary files with the tools needed for Linux platforms. When you need GnuPG for different platforms you need to compile this yourself. It would be appreciated when you make alternative installation methods for different platforms available to the general public.
Since development for the major part takes place with Linux (x86), translation to different systems should not be regarded as being a problem. The actual list of known operating systems that support GnuPG can be found on GnuPG Homepage. The procedure as described below is pretty platform independent. This procedure can be used to install GnuPG out of a source code tar-ball.
Unpack the tar-ball with the following commands, For sources compressed with gzip use:
tar xvzf gnupg-?.?.?.tar.gz
and for sources compressed with bzip2 use:
tar xvjf gnupg-?.?.?.tar.bz2
After the unpack, please step into the directory containing the source code. Then type
./configure
When doing this nothing special should happen. With
./configure --help
you can view the available configuration settings for compilation. If problems
occur that have to do with internationalization (gettext), you can include
a version that is delivered with the source code by using the option
--with-included-gettext or switch it of by using
the --disable-NLS option.
After this we want to compile the stuff by typing:
make
make clean, then run
configure again and retry to compile. If that doesn't work it is
time to panic.
Now type:
make install
usr/local/share/gnupg/ will be the installation directory. You can
find this directory in the file options.skel. When you change this
options.skel. If you copy this to ~/.gnupg/options the
appropriate adjustments will be used as standard. Copying should occur
automatically when creating ~/.gnupg/. All possible options are
well documented and explaining them here would not be useful.
You can run GnuPG as suid root. So the program runs with all the rights the
superuser has. By doing this you exclude the possibility that certain parts
of the program are stored externally and then could be read by anyone. It is
not feasible for me to judge on the value of this risk. But running the program
as suid root one should be alert to the danger of Trojan horses. Since a Trojan
horse running as superuser can damage an entire system. If for this reason (or
any other reason) you choose not run GnuPG as root you can switch off the warning
by setting
no-secmem-warning in ~/.gnupg/options.