$ sudo apt install p7zip-full
Add,
with password,
with header encryption,
with recursion,
unto ARCHIVE.7z,
FILES.
$ 7z a -p -mhe=on -r ARCHIVE.7z FILES
Extract ARCHIVE.7z here:
$ 7z x ARCHIVE.7z
KEY.pub and verify FILE:
$ gpg --import KEY.pub
$ gpg --verify FILE