I want to archive a directory and then encrypt it. And obviously get that directory back again sometime in future.
This will archive, compress, and encrypt:
tar -cz some-directory | gpg -c -o archive.tgz.gpg
And this will decrypt, decompress, and extract:
gpg -d archive.tgz.gpg | tar xz
This uses symmetric encryption with an AES128 cipher. AES128 is sufficient to protect classified information up to the SECRET level. Good enough for me.