FileLink’s Implementation of PGP

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First and foremost, FileLink is a scriptable file transfer package and not a comprehensive PGP encryption tool, but FileLink does provide the basic functionality required to utilize PGP.

 

FileLink is integrated with the open-source package named GnuPG from which FileLink obtains its PGP encryption/decryption engine.

 

The following functionality is provided by the FileLink Configurator:

 

•The creation of private and public key(s) and the creation of associated  “keyrings”
•The ability to export public keys to ASCII armored and non-ASCII armored files from a keyring to be shared with others (ASCII armored key files are plain-text files that are easily shared via e-mail or other means; non-armored files are in a binary format)
•The ability to import key(s) to a keyring
•The ability to delete key(s) from a keyring
•The ability to use existing FileLink or GPG keyrings

 

The following functionality is provided by script commands within FileLink itself:

 

•The ability to encrypt and optionally digitally sign files (the PGPENCRYPT command)
•The ability to decrypt files for which you have a corresponding public key (the PGPDECRYPT command)
•The ability to import public keys to a keyring (the PGPIMPORTcommand)

 

PGP has the added advantage of compression. Much like a zip file, files that are encoded using PGP are also compressed.  Of course, file(s) are expanded and restored to their original state when they are decrypted by their intended recipient.

 

PGP is a complex encryption technology and the preceding paragraphs barely scratch the surface as an introduction. If you are new to PGP specifically and public key cryptopgraphy in general, we strongly recommend doing some independent study on the subject to make sure that you understand the advantages and dangers associated with the encryption and decryption of files.

 

Extending FileLink’s PGP Functionality

 

In some cases, you may be required to encrypt or decrypt a file using a GnuPG option that is not directly implemented by FileLink. In order to do so, both the PGPENCRYPT and PGPDECRYPT commands support the /gpgopt option which allows you to specify any necessary GnuPG option(s). The /gpgopt option should be used by advanced users only and FileLink interoperability with all GnuPG options is not guaranteed.

 

The following example encrypts a file and specifies a supported option not directly supported by FileLink.

 

       PGPENCRYPT "in" "out" /user="Dick" /gpgopt="--force-v3-sigs"

 

Multiple GnuPG options may be passed using /gpgopt. When doing so, separate each complete option with a semi-colon as shown below.

 

       PGPENCRYPT ... /gpgopt="--force-v3-sigs;--no-verbose"

 

Be sure to always precede each GnuPG option with two dashes.

 

Troubleshooting FileLink’s PGP Functionality

 

For advanced troubleshooting, the PGPENCRYPT and PGPDECRYPT commands support  the /gpglog option which results in commands and responses to and from GnuPG (gpg.exe) being written to a log file.

 

The following example encrypts a file and writes to a log file named “encrypt.log”.

 

       PGPENCRYPT "in" "out" /user="Dick" /gpglog="encrypt.log"

 

If a fully qualified file name is not specified, the log file will be created in the current FileLink working folder. If the file exists, it will be appended to. Delete the file before each PGPENCRYPT or PGPDECRYPT command if you want only a single command to be logged.

 

The interpretation of the resulting log file is left to the user or the file may be requested by FileLink technical support to assist you with a particular problem.