How do I create an encrypted (password protected) zip file?
This will prompt for a password:
This is more insecure, as the password is entered/shown as plain text:
Warning, the standard zip encryption is very weak and is easily cracked.
You can also right-click on a folder or file(s) in Nautilus and select "Compress...". In the resulting window, you can expand the "Other Options" section to enter a password.
If the password field or any of the other options are not enabled, then the selected compression option does not support it. Select a different one from the list after the filename. According to the documentation: