Encryption & Security

MheePDF supports RC4-based PDF encryption (PDF 1.4 standard), allowing you to protect documents with user and owner passwords and restrict what readers can do with the file.

IMPORTANT

Encryption is configured in the MheePDF constructor. It cannot be added after generate() has been called.

How It Works

When encryption is enabled:

• A user password controls who can open the document.
• An owner password controls who can change permissions (e.g. remove restrictions via a PDF editor).
• Permission flags let you restrict printing, content copying, annotations, and modifications.

If only userPassword is set, the owner password defaults to an empty string (anyone with a PDF editor can remove restrictions). Set both for stronger control.

Options

Pass an encrypt object inside MheePDFOptions:

encrypt?: {
  userPassword?: string;
  ownerPassword?: string;
  permissions?: { ... };
}

Permissions

permissions

Option	Type	Default	Description
print	"none" | "low" | "high"	"high"	"none" disables printing entirely. "low" allows low-res print (screen). "high" allows full printing.
modify	boolean	true	Allow modification of document content.
copy	boolean	true	Allow copying text and graphics.
annot	boolean	true	Allow adding or modifying annotations and form fields.

Example

import { MheePDF } from "mheepdf";

// 1. Fully protected — requires password to open, prevents printing & copying
const securePdf = new MheePDF({
  pageSize: MheePDF.A4,
  encrypt: {
    userPassword: "open1234",
    ownerPassword: "admin9876",
    permissions: {
      print: "none",
      modify: false,
      copy: false,
      annot: false,
    },
  },
});

securePdf.addText("This document is confidential.");
securePdf.addText("Password required to open.");
const secureBuffer = securePdf.generate();

// 2. View-only — no password to open, but copying and printing are disabled
const readonlyPdf = new MheePDF({
  pageSize: MheePDF.A4,
  encrypt: {
    permissions: {
      print: "none",
      copy: false,
    },
  },
});

readonlyPdf.addText("You can read this document, but not copy or print it.");
const readonlyBuffer = readonlyPdf.generate();

// 3. Print-allowed, no modifications
const printablePdf = new MheePDF({
  pageSize: MheePDF.A4,
  encrypt: {
    userPassword: "print2026",
    permissions: {
      print: "high",
      modify: false,
      copy: false,
    },
  },
});

printablePdf.addText("Printable invoice — modifications restricted.");
const printableBuffer = printablePdf.generate();

NOTE

RC4 encryption satisfies most practical access-control needs. For highly sensitive content requiring AES-256 (PDF 2.0), consider a post-processing tool such as qpdf.