Encrypted tape archive solution?

Hi, I have a linux system and create tape archives every night. Most sensitive data files are encrypted, but I want the whole tape archive to be encrypted just for the peace of mind. Is there any simple solution for linux 2.0 that allows to create encrypted archives? Another question: suppose I use Matt Blase's CFS. Is it safe to backup the _encrypted_ files, and not the mounted directory that looks decrypted? (i.e., not the "attached" filesystem). Thanks, - Igor.