Create encrypted (password protected) zip file

Solution 1:

This will prompt for a password:

zip --encrypt file.zip files

This is more insecure, as the password is entered/shown as plain text:

zip --password (password) file.zip files

Warning, the standard zip encryption is very weak and is easily cracked.
Note, Use -r to zip directory and subdirectory recursively.

Solution 2:

Starting from Ubuntu 17.10, right-clicking and selecting "Compress" no longer has "Other Options" listed.

To resolve this, open "Archive Manager" and then drag & drop the files/folders from your File Manager into it and it will appear.

Solution 3:

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:

Currently, only 7-Zip, ZIP, RAR and ARJ archives support encryption

Solution 4:

Comments and answers have mentioned the default zip encryption is weak, but since there is no code example, here is on with .7zip:

sudo apt-get install p7zip-full  # install 7zip
7za a -tzip -p -mem=AES256 foo_file.zip foo_folder  # encrypt folder

Commands explained:

• 7za: Use 7zip
• a: Append? / Adding files? (e for extraction)
• -tzip: Use .zip format instead of default .7z
• -mem=AES256: Use AES256 encryption
• foo_file.zip: Name of .zip file
• foo_folder: Name of folder to encrypt

Answer based on: https://www.tecmint.com/7zip-command-examples-in-linux/