Use a Pipe() rather than a file to pass the passphrase to the command
line tool. Pass the file descriptor to read the passphrase from as fd '3'.
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Rather than passing the passphrase via command line write it into
a temp. file and pass the name of the file using passphrase-file option.
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>