A German software company has announced that it is offering a free encryption software program that can be plugged into Microsoft Outlook and used for e-mail.

The software, called GnuPG-Plugin, can be downloaded on the Web site of G DATA Software. It does not work with Outlook Express, and in order to function both the sender and receiver of e-mails must install the software.

Dirk Adam, head of content at G DATA Software in Bochum, told Newsbytes that the GnuPG-Plugin is based on an encryption software called GPG, which was developed a few years ago in Europe as an open-source project by Linux aficionados. But he said GPG did not have a "graphical user interface" and was geared toward true tech heads.

"It was very complicated to use," he explained. "You had to enter a long stream of parameters into your DOS box."

Adam said GnuPG-Plugin software has a graphical interface, and is simple for even non-techies to use. He said the program is similar to e-mail and attachment encryption software sold by PGP Security, which is now owned by Network Associates.

But GnuPG-Plugin has a big difference: the source code is open. This ensures that there are no so-called backdoors in the software, which allow people with knowledge of the code to slip in undetected and read encrypted messages.

"Some people are paranoid and do not want to use encryption software unless the source code is open," Adam said.

Adam said G DATA Software developed GnuPG-Plugin as part of a program sponsored by the German government. Development took about "two to three months," he said.

"It did not take very much time," he said. "It was not very complicated."

However, in just the few days since GnuPG-Plugin was officially launched, users have discovered a few technical bugs that are being fixed, Adam admitted. However, he maintained that is one of the strong points of open source software.

While the inner workings - the encryption tool and the organizing keys - of GnuPG-Plugin software are in English, the plug-in is in German. Many people downloading the software live outside of Germany, and requested an English plug-in. Adam said an English version will be available in a couple of weeks.

Meanwhile, the company will provide by e-mail English translations of the plug-in for those who request it.