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The -mhe switch in 7-Zip enables header encryption, which hides the file list in the archive until the correct password is provided. This adds an extra layer of security to your compressed files
7z a -p[password] -mhe=on [destination_file].7z [file_to_encrypt]
The man file in Ubuntu is horribly incomplete.
Use this one: https://linux.die.net/man/1/7z