encryption before tape backup

[Andy Cheong]

hi, do anyone have any idea what programs should i use so as to encrypt the
file before backing up.
currently i have a hp tape backup device. I am using tar to compress the
files and back up to the tape device.
should i tar the files first b4 encrypting them, or the other way round? but
what programs should i use?
by the way, have anyone use arcserve for linux? does it provide good backup
and encryption functions?

thanks a lot:)