Goal

Automatically encrypt all files in a folder with a PGP public key before they are being uploaded. Alternatively also sign the encrypted files with a PGP private key.

Solution

Prerequisite

Download and install the SmartFTP SDK
Download and install Gpg4Win-Light
License for SmartFTP Professional Edition or higher

Import the recepient's public key

Start the the GNU Privacy Assisant
Start Menu: All Programs - Gpg4win - GPA
Go to the menu Keys - Import Keys
Select the PGP public key file

Setup Transfer Queue Item

Start SmartFTP
Stop the Transfer Queue
Drag&Drop the folder you want to upload to the Remote Browser
A new item is created in the transfer queue
Right-click the item, select Properties from the context menu
Go to the Script dialog
Select the ApplyToFilesRecursively.js script from the SmartFTP SDK. Example:
C:\Program Files (x86)\SmartFTP Client SDK\Samples\TransferQueueItem\JScript\ApplyToFilesRecursively.js
For the Arguments use:
"C:\Program Files (x86)\SmartFTP Client SDK\Samples\TransferQueueItem\JScript\PgpEncryptFile.js"
including the double quotes.
Update the settings and paths in the PgpEncryptFile.js script
- Set the correct path to gpg2.exe
- Set the recipient key id
- Enable signature and set the signer if you also want to sign the encrypted file (Optional)
Click OK

Setup Scheduled Task

Right-click on the transfer queue item, select Schedule from the context menu
Click OK
Go to the Scheduler pane
Run the scheduled task: Right-click on the scheduled task and select Run
Go back to the Transfer Queue pane and start the queue

Notes

For debugging purpose you may want to disable the [ ] Use cached local folder tree option in the Queue Item action properties in the scheduled task.