Hi Nithin,
Here, I see you aim to execute several commands (encrypt file and then move file to another location). Having this in mind, it shall be convenient to develop a Linux script (for example, a bash script considering an OS your PI system runs) and call it from File/FTP receiver communication channel.
The first step is to prepare a script. I'm not aware of encryption library that you use, so it is not possible to provide you complete script code. But I'm sure you may work this out with the help of encryption library vendor / documentation and your colleagues responsible for Linux administration. As an outcome of this exercise, you shall get an executable script that calls encryption library for the file produced by PI, and then moves it to another location (NFS directory or FTP server). In receiver communication channel, you can use placeholder %f (file name) or %F (absolute file name - which is, file path and file name) when specifying the called OS command - so that the file name is passed as an argument to a called script, and script uses it when applying required actions to the file.
You can test if script works as expected from OS level, but placing a sample file (as if it would be produced by PI) and running a script with corresponding arguments from a shell.
After a script is ready, place it in a location that is accessible for PI application servers (or right on PI application servers).
In File/FTP receiver communication channel in PI, specify the same command that you used when testing a script, only adjusting file name argument (by replacing it with the placeholder) and specifying valid location of a script.
One important notice: since a file that is produced by PI, needs to be accessed, and considering the fact that File/FTP adapter triggers a calls of an OS command as a part of its execution, it may be the case that File/FTP adapter hasn't flushed corresponding file stream and closed it, so the file may not be available for the external program (e.g. OS commands) at a time of a script call (even in cases when a script is called after message processing) and a script will issue an error. If you observe this, as a workaround, you may want to put an explicit wait step right at the beginning of a Linux script so that at at time when script starts actual file processing (after wait), file receiver communication channel already completes its work and produces the file.
Regards,
Vadim