Protect PDF
Protect PDF files with AES-256 encryption on your device. Set and confirm an open password, choose reader permissions, then download the encrypted copy. An optional, separate owner password controls full access. No account or conversion-server upload is needed; files can be up to 50 MB.
How It Works
Get Your Result in 4 Simple Steps
Get a clean, usable result in just a few clicks — fast, easy, and completely free.
1
Choose an Unlocked PDF
Click Choose PDF or drop a file into the tool. Start with an authorized, unlocked original; already encrypted PDFs are rejected.
2
Set an Open Password
Enter and confirm the password people will need to open the document. Generate password creates a random password locally. The optional owner password must be different and confirmed separately.
3
Choose AES and Reader Permissions
Keep AES-256 for the default mode, or explicitly choose AES-128 for older-reader compatibility. Allow or restrict printing, copying, editing, comments, form filling and page assembly.
4
Encrypt and Check the Download
Click Encrypt PDF on this device, then Download protected PDF. Open the saved copy in your intended PDF reader and test its password before sharing. Send the password separately from the document.
Features
Everything You Need in One Tool
Built to be fast, clean, and easy to maintain — with no messy lines or hard-to-spot errors.
AES Encryption Without a Cloud Upload
Both AES-256 and AES-128 run in a browser worker. The software downloads from a CDN, but the widget does not send document bytes or passwords to a conversion service. If processing fails, it does not silently switch to weaker encryption.
Separate Open and Owner Passwords
An open password limits access to the document. A separate owner password gives full access in supporting readers. When omitted, an independent random owner password is generated for that output and is not retained. Set your own if you need it later.
Granular Permission Choices
Choose full-quality, low-resolution or no printing. Control copying, page-content editing, annotations, existing form filling and page assembly separately.
Confirmation and Fresh Download Results
Mismatched passwords disable encryption. Changing the file or settings clears the earlier download result. Cancel encryption stops the worker without producing a fallback file.
Common Use Cases
Who Is This Tool For?
Whether you're working on a personal project or a professional one, this tool fits right in.
-
Share a Private Report
Set an open password before sending a report or statement. -
Send a Form for Completion
Allow filling existing form fields while restricting other modifications. Test the form in the recipient’s PDF reader; permission combinations and interactive features can behave differently between applications. -
Request Read-Only Handling
Restrict content editing, page assembly or copying for a document intended for reference. Set an open password when confidentiality is required. -
Prepare Different Recipient Copies
Keep a secure original and create separate encrypted copies as needed. An already protected copy must be unlocked with authorization before it can be processed again.
Why It's Useful
Small Changes. Big Difference.
A little polish goes a long way — it saves time, reduces mistakes, and makes your work look more professional.
Choose a Long, Unique Password
Use the local generator or a password manager rather than a name or reused password. Encryption strength does not compensate for an easy-to-guess password.
Check the Password Type
The open password and owner password serve different purposes. Do not leave the open field blank when the goal is to stop unauthorized viewing.
Keep Compatibility in Mind
AES-256 supports Unicode passwords. AES-128 mode accepts printable ASCII passwords for compatibility. Passwords are limited to 127 UTF-8 bytes, and control characters are rejected.
Protect a Final, Reviewed Copy
Make needed changes before encryption using an appropriate PDF editor or Organize PDF. Rewriting may invalidate digital signatures; review forms and links too.
FAQs
Frequently Asked Questions
Find answers to the most common questions about this tool.
Choose an unlocked PDF, enter and confirm an open password, select AES and permissions, then click Encrypt PDF on this device. Download the result and test it. No account or payment is needed for this workflow.
The widget encrypts locally. Engine software downloads from a CDN on first use; document bytes and passwords are not uploaded by this workflow. Loading the website still uses an internet connection.
The open password is used to access the document. An owner password grants full access in supporting readers. They must differ. If the owner field is blank, a random owner password is generated and not saved for recovery.
Yes. Leave the open and confirmation fields blank and restrict at least one permission. The PDF opens without a password; restrictions depend on the reader.
AES-256 is the default. AES-128 is an explicit compatibility option for older readers. Neither mode falls back to RC4.
Use AES-256 for Unicode passwords. The password limit is 127 UTF-8 bytes, which may be fewer than 127 characters. AES-128 mode requires printable ASCII. Open and owner passwords cannot contain control characters.
No recovery or password storage is provided by this widget. Save your chosen passwords safely. Password fields remain in browser memory while the page is open; use Clear password fields or close the page afterward.
Not directly. Start with an original unlocked copy or unlock a document you are authorized to access. The tool rejects encrypted inputs instead of bypassing existing protection or claiming to overwrite it.
Possible causes include a damaged or encrypted source, a file over 50 MB, blocked software downloads or insufficient browser memory. No unprotected fallback is offered. Check the source and connection, then retry.
PDF rewriting can invalidate existing digital signatures. Check forms and links after saving. Permission restrictions do not guarantee copy prevention and cannot stop screenshots. Password protection is also different from verified redaction.
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