Password protect PDF with AES-256
Lock a PDF with a password using AES-256 encryption, so it can’t be opened without it; Refentra never stores the password.
- Runs in your browser
- No upload
- Check before download
Local file
Local file
Files and content stay on this device. Aggregate action counts are sent only with your separate consent. Plain unencrypted PDFs only: 10 MB/file, 20 pages, 10000 objects, no object streams, signatures, forms or complex navigation. Text and vectors remain. Page numbering supports unrotated pages. Real AES-256 opening-password encryption, not permission labels. Passwords are never persisted and are cleared after success. Keep your password: no recovery. Weak passwords remain vulnerable. 8–127 UTF-8 bytes.
Settings
- 8 to 127 characters (UTF-8 bytes, no control characters)
- Both entries are identical
A lost password cannot be recovered. Keep it somewhere safe.
Result
Local file
Password protect PDF with AES-256
- Prepare the input
Choose a supported PDF that isn't encrypted, enter an opening password and confirm it, and keep a secure, separate record of it. This applies real AES-256 password encryption, not a permissions label for show.
- Try the worked example
For a synthetic PDF and a password that is only for testing, the saved encrypted copy should ask for that password in a compatible reader. Confirm that a wrong password is refused and the right one opens the file before you rely on it for your real document.
- Check and save
Keep the unchanged original somewhere secure and store the password separately. The tool can't recover a forgotten password, and the fields are cleared after it succeeds. Never use the public example password for sensitive documents.
Questions
Does this only disable printing or copying?
No. It uses an opening password and real encryption. The permission settings of a reader aren't the same as protecting the contents of the file from being opened.
Will a weak password become safe because AES-256 is used?
No. Passwords that are easy to guess remain vulnerable. The profile accepts 8–127 UTF-8 bytes, which is not necessarily that many visible characters, and a matching confirmation doesn't show the password is strong.
Can the site recover the password later?
No. No password is stored or sent for recovery. Keep your own secure record and the original. This local tool can't restore access if you forget the opening password.
PDF password protection uses @libpdf/core0.5.1 (MIT). Copyright notice and original license