Protect PDF Online
Add a password to your PDF so only people you trust can open it.
Password protection is coming soon
True PDF encryption can't be done safely with free in-browser libraries yet — and we'd rather be honest than ship a fake lock. We're working on a proper solution.
Meanwhile, these tools are ready now:
Password protection is coming soon
We're building a tool to protect pdf files with a password — right in your browser, with nothing uploaded. It's not live yet, but here's what to expect and how to think about PDF security in the meantime.
What the tool will do
When it launches, you'll drop in a PDF, choose a strong password, and download an encrypted copy that can't be opened without it. Like every GroPDF tool, encryption will happen locally on your device — your file and your password will never leave your browser, which is the safest possible design for a password tool.
Choosing a good PDF password
- Length beats cleverness. A 16-character passphrase of random words (“correct horse battery staple” style) is far stronger than “P@ssw0rd!” and easier to remember.
- Don't reuse it. If the password also guards your email, one leak compromises both.
- Share passwords separately. Send the file one way and the password another — never in the same email.
What you can do right now
Until the tool launches, most PDF readers (including free ones) can set a password via their print or security menus — just be aware those files do get processed by that software. If you need to strip unneeded protection from a file you own today, Unlock PDF is already live. And if your document carries hidden data like author names, Clean PDF wipes it before you share.
What makes PDF encryption actually strong
Not all PDF passwords are equal. Modern PDF encryption (AES-256) is genuinely tough to break — but older PDFs may use 40-bit RC4 encryption, which a laptop can crack in minutes. When our tool launches, it will use modern strong encryption by default. The weakest link is almost always the password itself: “Summer2026!” falls to dictionary attacks regardless of the algorithm, while a long random passphrase holds up.
Encryption isn't the whole story
A password stops casual opening, but it doesn't stop screenshots, and it doesn't hide metadata — file properties like author name remain readable without the password. For maximum privacy, pair future password protection with Clean PDF to strip hidden data before sharing.
