Drop a PDF into the upload box. Then set a password and choose permissions before protecting it.
When you password-protect a PDF, you're telling the file to encrypt its own content. The PDF stores a cryptographic key derived from your password, and everything else — text, images, page structure — is scrambled using that key. Anyone who opens the file without the correct password sees garbage instead of readable content.
PDF has supported this since the very first version in 1993. It's not a Microsoft Word "mark as final" or a Google Docs "view only" — those are just UI tricks. Real PDF encryption is cryptographic. If you lose the password, the file is gone.
PDF has two different password slots. Most tools only use one. This tool lets you set both.
| Type | What it does | When it's asked |
|---|---|---|
| User password | The password to open the file. Without it, the PDF can't be decrypted. | Every time someone opens the PDF. |
| Owner password | A master password that overrides the permission restrictions. The file still needs the user password to open. | When someone tries to bypass a restriction (e.g. print when printing is disabled). |
In practice: set a user password so nobody can open the file without it. Set an owner password if you want to keep admin control. For 90% of cases, reusing the same password for both is fine.
Once someone opens the PDF, the permissions tell the reader what they're allowed to do. Not every PDF reader respects them — some paid tools ignore them entirely. But most modern PDF viewers honor them.
If off, most readers will refuse to print the document. Adobe Reader, Foxit, Preview, and Chrome's built-in viewer all respect this. Screenshots and screen-scraping still work — no permission system can prevent that.
If off, the reader blocks Ctrl+C on selected text. Also blocks the reader's "Save text as" feature. This is the permission most requested by HR departments and law firms — it protects content from being lifted into another document.
If off, most readers won't let you modify page content. Some readers gray out editing tools entirely; others allow editing but warn the user. Not all editors respect this — LibreOffice, for example, ignores it.
If off, readers block sticky notes, highlight, comments, and markup tools. Useful for documents you want reviewed but not marked up.
If off, form fields cannot be filled in. Common for forms that need to be filled by a specific person. If a form is meant to be filled out by recipients, leave this on.
This tool produces PDF standard security handler encryption — the same scheme Adobe Reader and every other PDF tool uses. That's RC4 128-bit, which is:
For documents that must withstand serious cryptographic attack — classified government records, high-value trade secrets — you need a tool that produces AES-256 with a proper security handler. That requires a backend or a native app. For everything else, RC4 128-bit is what the industry has used for 30 years.
Testing: open the downloaded file. Your PDF reader will prompt for the password. Try an incorrect password first, then the correct one, to confirm the encryption is real.
Every other online PDF password tool asks you to upload the file to their server — with the password. You're handing your confidential document and its password to a stranger's computer. For a public newsletter, that's fine. For an HR contract or a medical record, it's a serious risk.
This tool works differently. Everything runs inside your browser. The PDF is opened directly from your device's storage, encrypted in memory using JavaScript, and written back out. No upload, no server, nothing to leak.
You may have mistyped the password. Try opening with "confirm password" copy-pasted instead of typed. If it still doesn't work, re-encrypt a fresh copy with a shorter, simpler password — some older readers struggle with very long passwords or non-ASCII characters.
Not all PDF viewers honor the permission flags. Adobe Acrobat and Reader respect them fully. Chrome's built-in viewer honors print and copy. LibreOffice ignores editing restrictions. If you need guaranteed enforcement, deliver the file to users of Adobe Reader specifically.
Encryption overhead is tiny — a few KB at most. That's because the original pages aren't touched; only the encryption metadata and the file structure are added. A 5 MB PDF becomes a 5.01 MB PDF. That's normal.
No. And neither can anyone else. RC4 128-bit encryption isn't breakable by guessing, and there's no "backdoor." This is exactly the point — if the password could be recovered, the encryption wouldn't be secure. If you have the original (unprotected) file, re-encrypt from that.
That means the viewer doesn't support the encryption type or is refusing to prompt. Adobe Reader, Foxit Reader, macOS Preview, and Chrome all handle PDF RC4 encryption. Some lightweight viewers (older mobile apps, some browser extensions) don't. Tell recipients to use a proper PDF reader.
Yes — as long as you know the password. Use a dedicated "Remove Password" tool. This tool only adds protection; it doesn't remove it.
| Task | Tool | What it does |
|---|---|---|
| Require a password to open the PDF | Password Protect PDF | Encrypts the file so it can't be read without the password |
| Add your signature for approval | Sign PDF | Places a visible image signature on any page |
| Hide sensitive text before sharing | Redact PDF | Permanently blacks out content you don't want seen |
| Remove an existing password | Remove Password | Unlocks a file when you know the password |
| Shrink the file for email | Compress PDF | Reduces file size after protecting |
Yes. Here's exactly what happens when you use this tool:
At no point does the file or the password leave your device. No data is sent to SkillsInsider's servers. No tracking cookies watch your encryption. You can prove it yourself: turn off Wi-Fi after the page loads, then protect a PDF. It still works perfectly.
Yes — completely free. No sign-up, no watermark, no page limit. Use it as often as you need.
No. Encryption happens locally in your browser using a fork of pdf-lib. Your file and password never leave your device.
The output uses PDF standard security handler encryption — RC4 128-bit by default, which is widely compatible with every PDF reader. This is the same encryption used by Adobe's own "password protect" feature and by most online PDF tools.
The user password is what recipients type to open the file. The owner password is a master password that overrides the permission restrictions — useful if you want to keep editing rights yourself while restricting recipients. Set the owner password under "Advanced" in the sidebar.
That depends on the permissions you set. By default this tool allows printing, copying, and form filling. You can turn each off before encrypting. Most modern PDF readers respect these permissions.
There is no way to recover the password. This is by design — the encryption is real, not a soft lock. Save the password in a password manager before downloading. If you still have the original unprotected file, re-encrypt from that.
Once the page has fully loaded, yes. Turn off Wi-Fi and it still encrypts — all processing is local.
No. This tool only adds protection. To remove a password you already know, use a dedicated Remove Password tool. To remove a password you don't know — impossible without brute-forcing the encryption, which for RC4 128-bit takes centuries.
