Protect PDF
Local Processing (Offline Capable)Password-protect a PDF with AES-256, set printing and copying permissions locally.
How this tool works (no sign-up needed)
- Upload your file above. Each tool shows whether it runs Local (in your browser) or Cloud (encrypted servers).
- Adjust options, then click the Run / Convert / Process button.
- Wait for progress, then download the result. Use Next tools to continue.
If buttons are not visible, enable JavaScript — the interactive workspace loads in your browser.
Free · LocalAES-256 encryption, processed in your browser
Supports application/pdf
Owner password needs ≥4 chars
Local — your file is processed in your browser and not uploaded to us. No account needed.
What is it?Protect PDF is a PDFLean security & privacy tool: Password-protect a PDF with AES-256, set printing and copying permissions locally.
TL;DR: Password-protect a PDF with AES-256 and set printing and copying permissions locally. Everything runs locally in your browser — your file is never uploaded and is cleared when you close the tab; the owner password must be at least 4 characters (≤10MB).
Measured: ~42 ms median on a typical sample — full benchmark table below.
About this tool
Password-protect PDF files with standard AES-256 (or optional AES-128) encryption and configure granular permissions for printing, copying, and modifications. Processing runs entirely in your browser memory without file uploads, and your document is cleared immediately upon closing the tab. Free with no account required; owner password must be at least 4 characters; on-page limits apply (≤10MB).
Measured performance benchmarks
| Sample | Input | Output | Median time | Size change |
|---|---|---|---|---|
| Encrypt 60-page report (owner password, print allowed) | 160 KB | 162 KB | 42 ms | +1% |
Measured locally in your browser (isomorphic production code; samples are programmatically generated text PDFs, median of 5 runs). Real-world image-heavy PDFs differ — see the on-page limits.
How to use
Upload a PDF
Set the owner password and optional open password
Pick allowed permissions (printing, copying)
Click "Protect PDF" and download
FAQ
Will my file be uploaded?
No. Everything runs locally in your browser — your file is never uploaded and is cleared when you close the tab.
Are there any limits?
The owner password must be at least 4 characters; file size is limited to ≤10MB.
Is the protection strong enough?
Processing happens entirely locally in your browser; passwords and file contents never reach the server. Files are encrypted using ISO 32000-2 recommended AES-256 (optional AES-128).
Can I process multiple files in bulk?
A single tool page handles one task at a time; for bulk work use the Batch Processing workflow and add this tool as a step to run a whole set at once.
Is the processed file still editable?
Encryption is reversible — enter the password to open the file and remove restrictions at any time. Your original document remains untouched; you receive a newly encrypted copy. Be sure to remember the owner password, as it cannot be recovered if lost.