Create a password-protected ZIP
Do you need to send documents (an ID card, a payslip, a contract) and want to protect them with a password? Here you create a ZIP encrypted with 256-bit AES, and the files never leave your browser: no upload, no account.
Why not upload the files to a website
Almost all online «create zip with password» tools make you upload the files to their server to protect them — that is, you send out exactly the private documents you wanted to keep safe. Here it is the opposite: the ZIP is built inside your browser, the files and the password are not sent anywhere. You can even disconnect the internet after opening the page and it still works.
Real encryption: 256-bit AES, not the old ZipCrypto
The «classic» password ZIP (ZipCrypto) is broken in seconds with programs found online: it is fake protection. Here we use 256-bit AES encryption (the WinZip standard): the key is derived from the password with PBKDF2 (a thousand rounds, so trying passwords in bulk is very expensive), each file is encrypted and has an authentication code that notices if anyone touched the data. Without the password you read nothing.
What opens it
An AES ZIP opens with 7-Zip or WinRAR on Windows, with Keka or The Unarchiver on Mac, and also with a double-click on recent Windows 11. Note: the «Extract» function on older Windows and the Mac default one only open the old, weak ZIP, so with AES they will ask for one of the programs above. It is the price of serious encryption, and whoever receives the file usually already has it.
How it is checked to be right
The produced ZIP is opened by pyzipper (someone else's program that reads AES ZIPs) with the password: every file must come back identical to the original, and with the wrong password it must be rejected. The heart of the encryption, the AES block, is compared with the standard library's AES on many random cases. A file that looks protected but does not reopen, or that opens with the wrong password, would be the worst fault, and this test catches it.
What to know
The names of the files inside the ZIP are NOT hidden (they show in the list even without the password): only the content is under lock. And above all: if you lose the password nothing can be recovered, there is no shortcut — that is exactly what makes the encryption safe. To do the opposite, that is remove the password from an Office file, there is Remove the password from an Office file.