How to Password Protect an Existing ZIP File on Mac

Finder and Archive Utility only handle basic compression and extraction. Once a .zip file is created, macOS treats it as a finished file container with no option to modify its encryption state.

To protect it with built-in tools, you must double-click to unzip all files to a folder, open Terminal, and run zip -er protected.zip folder. This process takes time, clutters your drive with duplicate unencrypted files, and uses the outdated ZipCrypto algorithm by default.

File Acture's Protect Archive tool simplifies this into a single drag-and-drop step. When you drop an existing .zip, .7z, or .tar archive onto the tool, it securely repacks and encrypts the contents with 256-bit AES.

In the sidebar, select Protect Archive and drop your ZIP file. In Password and Confirm password, enter your desired password. You can keep the default name or type a custom Archive name, and select a Compression level: Normal, Maximum, or None (fastest). Click Protect.

The new archive is saved with “-protected” appended to the filename in your output folder. The original unencrypted ZIP remains untouched until you decide to delete it.

Older ZIP encryption (ZipCrypto) was designed in 1989 and can be broken in minutes using modern attack tools if an attacker has even one uncompressed file from the archive.

AES-256 is the gold standard for symmetric encryption, trusted by governments and security professionals worldwide. File Acture produces standard AES-256 ZIP files that open reliably in File Acture, 7-Zip, WinZip, and Keka on any platform.

Yes. Protect Archive accepts .7z, .tar, .gz, .bz2, and .xz archives as well as standard .zip files. It processes the archive and outputs a clean, universally compatible AES-256 encrypted ZIP file.

If you want to create an encrypted ZIP from loose files rather than an existing archive, you can also use Create ZIP.