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Saturday, August 17, 2013

Comments and Caveats in using Portable GPG Shell - gpg4usb

At the on set, let's me congratulate the developers in Gpg4Usb for releasing a very useful GPG shell that is portable in Windows and portable in a sense in Linux. The same distribution can run in Windows and in Linux, with some caveats as discussed below.

You can download a copy from here and unzipping it into a folder in Windows or Linux and you can immediately use it by running the program start_windows.exe. In Linux, you start the program by launching the start_linux program.

While it cannot do all the stuff that Gpg4Win can do in Windows, the beauty of Gpg4Usb is that it is self-contain and can run off the USB drive in any Windows without Administrative Privilege. It carries a copy of gpg.exe for Windows and gpg for Linux in the bin folder. The keys, using the standard format used by gpg.exe, are kept in the keydb folder.

Since there is no special treatment needed to get this program running in Windows from your local hard drive or your USB drive, let's move the discussion onto running this from Linux.

Through no fault of this program if located on USB drive, the default way of mounting the USB drive in Linux forbids one to execute any binary from such a device. Hence it is not as portable as in a Windows environment where there is no such restriction.

Without root access, the only viable option is to copy the gpg4usb folder onto a local drive (into the home folder if you like) from the USB drive. If you have updated any keys while using this program directly from the USB drive in Windows, all you have to do is just to update the gpg4usb/keydb folder on your local drive. Once you have done that, the following caveats apply:

1) Make sure you change the file permission of the following files to have executable permission:

Failure to do so will not launch anything and there is no crash message. If you simply give gpp4usb/start_linux executable permission, in a 32-bit Linux, the program will start but you will not see the keys in the key store. This is because the program fails to launch gpg4usb/bin/gpg necessary to retrieve the keys.

2) In a 64-bit Linux you need to ensure that you have 32-bit binary support. In Debian/Ubuntu derivative distro, such as Mint, you need to use the Software Manager to install the package ia32-libs-multiarch.

Without that package the program will not start even if the Caveat 1) above has been applied. I would recommend to try to run the program after applying the changes mentioned in caveat 1) first just in case some other 32-bit program may have installed the 32-bit support for you.

This program, despite the above caveats in Linux, is a competent replacement of GPA that is not longer supported and even KGpg.

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