AES-256 PDF protection

Protect PDF with a Password

Add a password required to open your PDF. Setpdf applies standard AES-256 PDF encryption and preserves the document's pages, order, dimensions and metadata.

Drop your PDF here

Select one valid, unencrypted PDF up to 50 MB.

Password strength

Not set

Strength is only a reference and never blocks protection. Any non-empty password is accepted; choose one suitable for how you will share the file.

Required when any restriction is selected. It must differ from the opening password.

Ask PDF readers to disallow:

Encrypted on Setpdf's server over HTTPS. Files are deleted immediately after processing; passwords are not logged or retained.

What PDF password protection can do

Use standard document encryption to control who can open a sensitive PDF.

Require a password to open

Recipients must enter the correct opening password before a compatible reader can decrypt and display the document.

Encrypt document objects

AES-256 encrypts PDF streams and strings, including document content and metadata, using the standard PDF security handler.

Request reader permissions

An optional owner password can request printing, copying, editing and annotation restrictions in compliant PDF readers.

What it cannot guarantee

It cannot prevent screenshots, photographs or screen recording after an authorized user opens the file.

It cannot prevent OCR or re-creation of content that a recipient can already view.

Permission restrictions are not absolute and may be ignored or removed by some software.

No encryption can compensate for a weak, reused, shared or exposed password.

Opening password vs. permissions password

The opening password encrypts access to the document. Without it, a compatible reader cannot decrypt the PDF content.

The permissions password, also called the owner password, controls security settings and requested usage restrictions. Readers enforce those restrictions, so they are less absolute than the opening password.

Common uses for protected PDFs

Contracts

Share draft agreements or signed copies through a separate password channel.

Invoices

Limit casual access to customer, billing and payment details.

Financial files

Protect statements, forecasts and internal financial reports in transit.

HR documents

Add access control to reviews, payroll records and employee documents.

Legal files

Protect privileged correspondence, evidence bundles and case documents.

Encryption and compatibility

Setpdf uses AES-256 with PDF security revision 6. It works with current Adobe Acrobat, major desktop PDF applications and modern browsers. Very old PDF readers may not support AES-256 files.

If you forget the password

Setpdf never retains a recoverable copy of your password. A strong forgotten password can make the PDF permanently inaccessible, so store it in a trusted password manager and share it separately from the file.

File handling and deletion

The PDF is sent over HTTPS to Setpdf for encryption. A private temporary task directory is created, the password is passed to the encryption process through standard input and is never written to a command line or log, and all input and output files are deleted immediately after the response finishes. Setpdf does not retain the file or password.

How to password-protect a PDF

STEP 1

Upload the PDF

Choose or drag in one valid PDF that is not already encrypted.

STEP 2

Set a strong password

Enter and confirm a password, or generate a strong one and save it safely.

STEP 3

Review optional permissions

If needed, add a different permissions password and select reader restrictions.

STEP 4

Protect and download

Apply AES-256 encryption and download the protected PDF.

Protect PDF questions

Setpdf uses standard AES-256 PDF encryption with security revision 6. The result is designed for current PDF readers.

No. Setpdf does not retain your password, so it cannot recover or reset it. Keep a secure copy before sharing or closing the page.

Yes. The process preserves page content, order, dimensions and document metadata. The PDF is rewritten only as needed to apply encryption.

No. Those permissions are requests enforced by compatible PDF readers. Some tools can ignore or remove them, so use them as a deterrent rather than absolute access control.

No. Anyone who can legitimately view the document may still capture the screen, photograph it or run OCR. PDF encryption controls opening, not what happens after authorized viewing.

No. The PDF exists only in a private temporary task directory during processing and is deleted with the encrypted output immediately after the response. The password is passed in memory to the encryption process and is not logged or retained.