Backup Exec 2010 - Encrypting or password protecting tapes

Hi,

I've been looking into protecting our backup tapes with either encryption or password protection.

We basically perform a backup to disk onto the backup exec server every night and then a duplicate job copies these to tape. We are using a HP StorageWorks Ultrium 920 LTo3 drive.

I know that encryption is going to add an overhead to our jobs so I thought it could just be added to the duplicate tape jobs that copy data to the tapes - not the actual backup to disk jobs. Is this feasible?

Would this have inpact on the backups that are done to disk?

Is the above drive capable of hardware encryption or do I need to set software encryption? Is another option just top password protect the tapes - although I can't see this option?

Thanks in advance.