Currently, I use tar to write my backups (ntbackup files) to a tape drive fed by an autoloader.

Ex: tar -F /root/advancetape -cvf /dev/st0 *.bkf (/root/advancetape just has the logic to advance to the next tape if there is one available or notify to swap the tapes out)

I was recently handed the requirement to encrypt our tape backups. I can easily encrypt the data with no problems using GPG. The problem I'm having is how do I write this to multiple tapes with the same logic that tar uses to advance the tapes once the current one is filled? I cannot write the encrypted file to disk first (2+TB). As far as I can tell, tar will not accept binary input from stdin (it's looking for file names). Any ideas? :(