Protect PDF Online — add password protection directly in your browser
Simple mode sets an open password in seconds. Advanced mode provides encryption options, a separate permissions password, and fine-grained controls for printing, copying, and editing.
Your password never leaves your browser. Encryption happens locally — your file and password are never uploaded, transmitted, or stored on our servers.
The protection console
Upload a PDF, choose a mode, and set your password.
We never see or store your password. Encryption happens entirely in this browser tab. Nothing is uploaded to our servers.
Drop your PDF here
or browse files
Password protection for your PDF files
Protect PDF adds password-based protection to your PDF and creates a new protected copy. Choose the encryption option supported by your workflow, then download the result.
What this tool genuinely does
- Encrypts the document's actual content — strings and streams — using standard RC4 or AES security handlers.
- Writes a standard encryption dictionary into the file, so supported PDF readers will require the password to open it.
- Supports separate open and permissions passwords in Advanced mode, matching standard desktop PDF configurations.
- The supported encryption paths have been checked with representative PDF files and password open/reject tests.
Where it stops short
- Cannot change the password on an existing 256-bit AES protected upload — that decryption path uses a different algorithm. Use Unlock PDF first for those files.
- Permission restrictions (like disabling printing) are respected by compliant software, not enforced as a hard technical barrier — see the FAQ for what that means in practice.
- Cannot protect against someone who already has an unprotected copy of the same file from before you added a password.
Four steps, as simple or detailed as you need
Simple mode gets you a protected file fast; Advanced mode gives you full control.
Upload your PDF
Drag it onto the upload area, or click Select PDF.
Choose Simple or Advanced
Pick the mode that matches what you need:
Confirm and apply
You'll be asked to confirm before the password is applied — there's no undo once it's set.
Download the protected file
Your original file is never modified — only the new, protected copy is downloaded.
When a PDF needs a real password
Common, legitimate reasons to add protection before sharing a file.
| Use case | Why protection helps | Typical user |
|---|---|---|
| Sharing financial statements | Require a password before an emailed statement or invoice can be opened. | Accountants & finance teams |
| Sending contracts for review | Restrict printing or editing while a draft is still under negotiation. | Legal & business teams |
| Distributing internal reports | Keep a document readable but prevent casual copying or reprinting. | HR & operations teams |
| Protecting personal records | Add a password to scanned IDs or medical documents before storing them. | Individuals managing records |
| Selling digital documents | Share a password-protected PDF with customers after completing your payment or delivery process. | Independent sellers & creators |
| Submitting official forms | Lock a completed form so it can't be altered before submission. | Anyone filing official paperwork |
What each Advanced permission actually controls
These map directly to standard PDF permission flags — here's what each one honestly does and doesn't guarantee.
Document open password
The strongest control here — without it, a compliant PDF reader won't display the document's content at all. This is what "Simple mode" sets by itself.
Permissions password
A separate password required only to change the restrictions below — useful when you want the document freely readable but its permission settings locked to a password you control.
Printing & modification restrictions
These set standard PDF permission flags that well-behaved software checks before allowing the action. They are not a technical barrier that makes printing or editing impossible — a reader that ignores the flag can still allow it.
Copying & accessibility
These are independent flags — you can allow screen readers to access text for accessibility purposes even while disabling general copying, matching what the toggles show separately.
When something doesn't work as expected
What's actually happening, and the fastest way through it.
"Apply password" stays disabled
The password and confirmation fields don't match yet, or one is empty.
Check both fields show the exact same password before continuing.
Can't change the password on an already-256-bit-AES-protected file
Decrypting an existing 256-bit AES file uses a different algorithm that hasn't been implemented here.
Use Unlock PDF first, then re-upload the unlocked file to add new protection.
A printing or editing restriction didn't stop someone
Permission flags are respected voluntarily by well-behaved PDF software — they aren't a hard technical block.
For content that must never be printed or copied, use an open password instead of relying on permissions alone.
I forgot the password after applying it
Passwords aren't stored anywhere, including by this tool — there's no way to recover a forgotten one.
If you kept the original unprotected file, start over from that; otherwise the password can't be recovered.
"Lock" button stays disabled in Advanced mode
The open password field is empty while "Require a password" is turned on, or the permissions password is missing while restrictions are enabled.
Fill in whichever password field corresponds to the toggle you've enabled.
"Apply password" disabled
Why: Passwords don't match yet.
Fix: Check both fields match exactly.
Can't change password on 256-bit AES file
Why: Different, unimplemented decrypt algorithm.
Fix: Use Unlock PDF first, then re-upload.
Restriction didn't stop someone
Why: Permissions are voluntary, not enforced.
Fix: Use an open password instead.
Forgot the password
Why: Never stored anywhere.
Fix: Restart from the original file if kept.
"Lock" button disabled
Why: A required password field is empty.
Fix: Fill in the matching password field.
Protecting without locking yourself out
A few habits that avoid the most common regret.
Write the password down somewhere safe
There's no recovery option if you forget it — a password manager or secure note is worth the extra step.
Keep the unprotected original
If you ever need to change the password or remove it, starting from the original is far easier than working around a forgotten one.
Use Advanced mode for shared or reviewed documents
Separate permissions passwords let you keep a file readable while still controlling who can edit its settings.
Send the password through a different channel
If you're emailing the protected file, share the password by text or phone instead, so the two aren't both exposed if one channel is compromised.
Choose a password you wouldn't reuse elsewhere
Since this password may end up shared with others to open the file, avoid reusing a password tied to a personal account.
Rely on an open password for anything truly sensitive
If content must never be printed, copied, or read without authorization, don't depend on permission restrictions alone.
Protect PDF FAQs
Start with the first question if you're deciding whether to trust this for something sensitive.
Is this real password protection, or just a viewer-side lock?
This tool writes standard PDF encryption data into a new protected copy of your file. Supported PDF readers should require the document password when opening the file, although compatibility can vary by reader and encryption option.
What's the difference between Simple and Advanced mode?
Simple mode sets one password that's required to open the file, with no other restrictions, using AES-128 encryption. Advanced mode lets you choose the encryption strength, set a separate permissions password, and restrict specific actions like printing or copying independently of whether the file can be opened at all.
Why did 256-bit AES take extra explaining?
256-bit AES uses a more complex PDF encryption process than RC4 or 128-bit AES. This option is available for new files, but compatibility can vary between PDF readers. Existing 256-bit AES files cannot currently have their password changed directly in this tool.
I uploaded a PDF that already has a password — can I change it?
Yes, for files protected with RC4 or 128-bit AES: enter the current password to unlock it, then set a new one with Simple or Advanced mode as usual. Files protected with 256-bit AES can't have their password changed here yet — use Unlock PDF first, then re-upload the unlocked file to add new protection.
Do you store or see the password I set?
No. The password is processed locally in your browser and is not sent to our servers by this tool. Keep a secure copy of your password because it cannot be recovered here.
Can permission restrictions (like disabling printing) actually stop someone determined?
Permission flags are enforced by compliant PDF software, but they are not a guaranteed barrier against determined users. Use an open password when the document itself must remain strictly inaccessible.
How encryption is handled in this tool
PDF standard security handlers specify exact key-derivation and validation routines. Standard cryptographic primitives were structured into this browser tool to ensure that documents are encrypted properly and recognized across standard PDF reading software.
Compatibility and testing
Sample test documents were protected with user and owner passwords, then tested to verify that valid passwords unlock the content accurately while incorrect passwords are rejected by PDF viewing software.