PDF encryption is the most reliable way to ensure only authorized recipients can open your documents. Here is how to encrypt any PDF using industry-standard RC4-128-bit encryption — for free in your browser.
PDF encryption uses a password-based cipher to scramble the document content. Without the correct password, the file cannot be opened or read. The RC4-128 standard used by pdfeditor.onl is compatible with Adobe Acrobat and all major PDF viewers.
Upload your PDF, enter your password, and click Protect PDF. The encryption runs entirely in your browser — your file is never sent to a server.
In addition to an open password, you can set an owner password to restrict actions like printing, copying text, or editing even for users who can open the PDF.
Tip: Combine an open password with print restrictions for maximum protection — ideal for confidential reports distributed to clients.
For most business and personal use cases, yes. RC4-128 is a widely supported PDF encryption standard. For top-secret government or financial data, consider AES-256 encryption via a dedicated security tool.
Yes. RC4-128 encrypted PDFs are supported by Adobe Acrobat, Apple Preview, Foxit, and browser-based PDF viewers.
Yes — completely free at pdfeditor.onl/protect-pdf.