Password Protect Zip Files in Mac OS X

Zip Password in Mac OS X

Creating a password protected zip file is easy in Mac OS X and does not require any add-ons or downloads. Instead, use the zip utility that is bundled with all Macs.

If you're familiar with the command line, the syntax of the encrypted zip command is as follows:
zip -e [archive] [file]

If you're not sure how to use that, read on to learn how to create zip archives encrypted with passwords. These encrypted zip files will maintain password protection across platforms, meaning you can send a protected zip file to a Windows user and they will still need to enter the password in order to view the contents.

Set a Zip Password in Mac OS X

You can create password protected archives of files and folders:

Launch the Terminal from the Applications > Utilities folder
Type the following command:

zip -e archivename.zip filetoprotect.txt

Enter and verify the password – don't forget this

The resulting archive, in this case named "archivename.zip", is now encrypted with the password provided. The file that was encrypted, "filetoprotect.txt", is now inaccessible without entering that password.

Example: Zipping a Folder and Setting a Password
Here is an example of what this will look like from the command line, in this case we are compressing and password protecting the entire 'Confidential' folder located within the users /Documents directory, and the password protected zip is being placed on the users desktop for easy access:
$ zip -e ~/Desktop/encrypted.zip ~/Documents/Confidential/ Enter password: Verify password: adding: ~/Documents/Confidential/ (deflated 13%)

Notice the password will not display, this is normal behavior for the Terminal.

Opening the Password Protected Zip

Despite being created at the command line, you do not need to unzip the file from the terminal, it can be expanded from the Mac OS X Finder or within Windows using standard unzipping apps. Just double click on the file, enter the password, and it will decompress. You can also decompress the zip archive from the command line with:
unzip filename.zip

Here are some use cases for password protected zip archives:

Password protecting an individual file or directory
Sending a sensitive and encrypted file over an unencrypted network
Emailing confidential data to a Windows user
Adding an additional layer of security to a hidden folder
Password protecting your own backups, outside of Time Machine

While this can provide some protection on a per-file or folder basis, it's always a good idea to password protect the Mac in general with a login requirement on system boot, wake from sleep, and waking from the screen saver.