Password-protect a ZIP file

What the password protects, and what it does not

In a ZIP, the password locks what is in each file. The list of names stays readable: anyone can see that the ZIP holds Tax return 2025.pdf, but not open it. If the names themselves give too much away, make a 7Z instead: with a password, 7Z encrypts the names too, and without it nobody can even list the contents. See make a 7Z file.

The password is not stored anywhere. Octoolo cannot recover it, and neither can anyone else: if it is lost, so are the files. A long passphrase of several words is both easier to remember and harder to guess than a short tangle of symbols; Octoolo's password generator makes either.

Who can open it

The older ZipCrypto lock, which Explorer can open, is easily broken, so Octoolo does not make it. It does open ZipCrypto ZIPs others send you, as it opens AES ones: see unzip files.

A password ZIP or a locked file?

A ZIP with a password is for sending: whoever gets it opens it with any archiver that reads AES. To keep files private on your own PC, the Lock door in Files is the better fit: a file or folder becomes one locked file that hides the names too, and the original goes once the locked file checks out. See lock a folder and password-protect a file.