Protect PDF
Password-protect your PDF documents to restrict access and prevent unauthorised viewing or editing.
Browser Limitation
PDF password encryption requires server-side processing because the browser's PDF libraries (pdf-lib) don't support encryption natively. This feature is planned for a future server-side integration.
Available Alternatives
Watermark PDF
Add a visible "CONFIDENTIAL" or custom watermark to all pages
Use Adobe Acrobat or Preview (Mac)
Both support full AES-256 password protection. In Preview: File → Export as PDF → Show Details → check Encrypt.
Coming Soon
Server-side PDF encryption with zero-knowledge architecture is planned. Your file will be encrypted before upload and deleted immediately after.
Owner Password
Set an owner password to prevent editing, copying, or printing without authorisation.
User Password
Set a user password so the document can only be opened by people who know it.
Standard Encryption
PDF password protection uses AES-128 or AES-256 encryption, widely supported by PDF readers.
About PDF password protection
PDF password protection lets you add an open password (so only authorised recipients can view the document) or an owner password (to restrict printing, copying, and editing). The PDF standard supports AES-128 and AES-256 encryption, both of which are recognised by Adobe Acrobat, Apple Preview, and most modern PDF readers.
This feature is currently in development for ConvertForge. In the meantime, the alternatives listed in the tool above — including Watermark PDF and the desktop options — cover most document-security needs.
Why browser-based PDF encryption is complex
The pdf-lib library used for most ConvertForge PDF tools does not support AES encryption natively. Implementing it requires either a full client-side cryptography layer (which adds significant bundle size) or a minimal server-side step where the file is encrypted and immediately discarded. ConvertForge is working on a zero-knowledge approach — encrypting on the client before any server contact — so your document content is never exposed. Until that is ready, use the alternatives shown in the tool or a desktop application like Adobe Acrobat or Apple Preview.
Privacy commitment
ConvertForge's goal for all PDF tools is 100% browser-based processing — files never leave your device. For PDF encryption specifically, the planned implementation uses client-side cryptography so that even if a server-side coordination step is needed, your PDF content is encrypted before it ever leaves the browser. No plaintext document data will be transmitted.
Frequently Asked Questions
When will PDF password protection be available?
This feature is planned but not yet launched. The tool page shows honest alternatives in the meantime. Follow ConvertForge for updates.
Why can't the browser encrypt PDFs right now?
The JavaScript PDF library (pdf-lib) does not implement AES encryption natively. Adding it requires either a large WASM cryptography module or a server-side step — both of which need careful privacy-first design before launch.
What can I use to password-protect a PDF today?
On Mac, open the PDF in Preview → File → Export as PDF → Show Details → tick Encrypt and set a password. In Adobe Acrobat, use File → Protect Using Password. Both support AES-256 and are free on their respective platforms.
Will it be free when it launches?
Yes — like all ConvertForge tools, PDF protection will be free with no account or subscription required.