Protect a PDF with a Password
Add an open password to any PDF so that only people who know it can view the document. The file is encrypted with AES, the encryption standard supported by every modern PDF reader — Adobe Acrobat, browsers, and phone apps will ask for the password before showing the content.
The processing happens on our server: your file is uploaded, encrypted and streamed back to you for download. Neither the file nor the password is stored afterward.
Why Use This Tool to Lock PDF Files?
- Strong AES encryption supported by all modern PDF readers
- Protect several PDF files at once with the same password
- The content, layout and quality of the document stay exactly the same
- No installation, sign-up or watermarking of your document
How to Password-Protect a PDF
- Drag and drop your PDF file, or click to select one
- Enter a password twice, then click the "Lock PDF" button
- Your protected PDF downloads automatically once processing finishes
Frequently Asked Questions
Is this PDF protection tool free?
Yes, password-protecting your PDF files is completely free.
How secure is the protection?
The file is encrypted with AES-128. Its security depends mostly on the password: use at least 10 characters mixing upper- and lowercase letters, digits and symbols (up to 32 characters).
Are my file and password kept private?
Your PDF and password are sent to our server only for the duration of the encryption, processed in memory, and discarded immediately afterward — they are not stored.
Is there a file size limit?
Yes, uploaded PDF files must be 1 GB or smaller.