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Add a Password to a ZIP File
Password protect a ZIP file online for free with AES-256 encryption. Choose strong AES or Windows-compatible ZipCrypto. No signup, no watermark, files deleted automatically.
About this Protect ZIP tool
Protect ZIP encrypts an archive so its contents cannot be opened or even listed without the password. Upload a ZIP, choose a password, and the archive is rebuilt with real encryption applied to every file inside. You can pick between two standards. AES-256 is the strong, modern choice and is what you want for anything genuinely sensitive — contracts, payroll, scans of identity documents, client data — and it is opened by 7-Zip, WinRAR, Keka, and the archive tools built into macOS and Linux. ZipCrypto is the older method, and its one advantage is that Windows File Explorer can open it without any extra software; its encryption is weak and should be treated as a deterrent rather than protection. Whichever you choose, store the password somewhere safe first: an encrypted archive has no recovery route, and neither we nor anyone else can open it for you if the password is lost.
How to use Protect ZIP
- Open the tool and add your file, text or values.
- Review the available options such as page range, output format, quality, password or language.
- Start the process and keep the browser window open until it finishes.
- Download the result and continue with a related tool if needed.
Useful tips
- For scanned PDFs, tools with OCR support run text recognition automatically where possible.
- For large files, use compression tools before sharing by email or uploading to portals.
- For best results, upload clean files with the correct extension and avoid corrupted documents.
When a password-protected ZIP is the right tool
Emailing documents containing personal data — payslips, tax papers, medical letters, ID scans. Email itself travels unencrypted, so encrypting the attachment is the practical safeguard.
Sending a batch of files to a client or colleague where you want one password to cover the whole set rather than protecting each document individually.
Storing an archive in cloud storage or on a USB drive that other people can reach.
What ZIP encryption does not do
It does not hide the file names inside the archive, only their contents.
It does not prove who created the file or that it has not been tampered with — encryption protects confidentiality, not authenticity.
ZipCrypto in particular is breakable by well-known techniques when an attacker has part of the original content, so use AES-256 whenever the recipient can open it.
Frequently asked questions
Should I choose AES-256 or ZipCrypto?
AES-256 unless the person receiving the file must open it using the ZIP support built into Windows, which only understands ZipCrypto. AES-256 is genuinely strong encryption; ZipCrypto is an old method with known weaknesses and should be treated as a deterrent.
Can the recipient open an AES-256 ZIP?
Yes, with any modern archiver — 7-Zip and WinRAR on Windows, Keka or The Unarchiver on macOS, and standard tools on Linux. Only the ZIP feature built into Windows File Explorer cannot, which is the reason the ZipCrypto option exists.
Does the password hide the file names too?
The contents are always encrypted. File names inside the archive remain visible with the standard ZIP format, so avoid putting sensitive information in the file names themselves.
What happens if I forget the password?
The archive cannot be opened. That is the entire point of encryption — there is no backdoor and no recovery. Save the password in a password manager before you send the file.
How should I send the password to someone?
Through a different channel than the file. Email the archive and send the password by text message or phone, so that one intercepted message does not hand over both.
My ZIP is already protected — can I change the password?
Remove the existing password first with the Remove ZIP Password tool (you will need the current one), then protect the result with your new password.
Is there a size limit?
Uploads up to 512 MB, holding up to 2 GB of uncompressed content, are supported.