Password-Protected PDFs in Linux

Information

PSPDFKit Processor has been deprecated and replaced by PSPDFKit Document Engine. All PSPDFKit Processor licenses will work as before and be supported until 15 May 2024 (we will contact you about license migration). To start using Document Engine, refer to the migration guide. With Document Engine, you’ll have access to robust new capabilities (read the blog for more information).

PSPDFKit Processor enables you to work with password-protected PDFs. You can provide password-protected PDFs as inputs for PSPDFKit Processor’s operations and password protect the output of these operations.

Before you get started, make sure Processor is up and running.

You can download and use either of the following sample documents for the examples in this guide:

You’ll be sending multipart POST requests with instructions to Processor’s /build endpoint. To learn more about multipart requests, refer to our blog post on the topic, A Brief Tour of Multipart Requests.

Check out the API Reference to learn more about the /build endpoint and all the actions you can perform on PDFs with PSPDFKit Processor.

Performing Operations on Password-Protected PDFs

To merge a password-protected PDF with an unprotected PDF document, use the following example:

curl -X POST http://localhost:5000/build \
  -F document=@/path/to/example-document.pdf \
  -F password-document=@/path/to/example-password-document.pdf \
  -F instructions='{
  "parts": [
    {
      "file": "document"
    },
    {
      "file": "password-document",
      "password": "123456"
    }
  ]
}' \
  -o result.pdf
POST /process HTTP/1.1
Content-Type: multipart/form-data; boundary=customboundary

--customboundary
Content-Disposition: form-data; name="document"; filename="example-document.pdf"
Content-Type: application/pdf

<PDF data>
--customboundary
Content-Disposition: form-data; name="password-document"; filename="example-password-document.pdf"
Content-Type: application/pdf

<PDF data>
--customboundary
Content-Disposition: form-data; name="instructions"
Content-Type: application/json

{
  "parts": [
    {
      "file": "document"
    },
    {
      "file": "password-document",
      "password": "123456"
    }
  ]
}
--customboundary--
Warning

The PDF documents you create with /build are unprotected by default. For more information on setting a password for a document, see the guide on Output.

Password Protecting the PDF Output

It’s possible to protect PDF files with passwords to control who can access, modify, and print a document.

PDFs are protected with two types of passwords: the user password and the owner password.

  • A user can open the document but they might have limited access to it depending on how the owner configures user permissions.

  • An owner has full access to the document. They can change the PDF file, the user password, and the user permissions. These permissions control what the user can do with the file, such as view, print, copy, or modify the contents.

Specify what users can do to a password-protected document with the user_permissions parameter. The value of this parameter is an array, where each element is one of the following:

  • annotations_and_forms allows users to add or modify text annotations and fill in interactive form fields.

  • assemble allows users to insert, rotate, or delete pages and create document outline items or thumbnail images.

  • extract allows users to copy or otherwise extract text and graphics from the document.

  • extract_accessibility allows users to copy or otherwise extract text and graphics from the document using accessibility options.

  • fill_forms allows users to fill in existing interactive form fields (including signature fields).

  • modification allows users to modify the document in any way not covered by the other permissions settings.

  • print_high_quality allows users to print the document in high quality.

  • printing allows users to print the document.

To password protect the PDF output from /build, use the following example:

curl -X POST http://localhost:5000/build \
  -F cover=@/path/to/cover.pdf \
  -F document=@/path/to/example-document.pdf \
  -F instructions='{
  "parts": [
    {
      "file": "cover"
    },
    {
      "file": "document"
    }
  ],
  "output": {
    "type": "pdf",
    "owner_password": "owner-password",
    "user_password": "user-password",
    "user_permissions": [
      "printing",
      "modification",
      "extract",
      "annotations_and_forms",
      "fill_forms",
      "extract_accessibility",
      "assemble",
      "print_high_quality"
    ]
  }
}' \
  -o result.pdf
POST /process HTTP/1.1
Content-Type: multipart/form-data; boundary=customboundary

--customboundary
Content-Disposition: form-data; name="cover"; filename="cover.pdf"
Content-Type: application/pdf

<PDF data>
--customboundary
Content-Disposition: form-data; name="document"; filename="example-document.pdf"
Content-Type: application/pdf

<PDF data>
--customboundary
Content-Disposition: form-data; name="instructions"
Content-Type: application/json

{
  "parts": [
    {
      "file": "cover"
    },
    {
      "file": "document"
    }
  ],
  "output": {
    "type": "pdf",
    "owner_password": "owner-password",
    "user_password": "user-password",
    "user_permissions": [
      "printing",
      "modification",
      "extract",
      "annotations_and_forms",
      "fill_forms",
      "extract_accessibility",
      "assemble",
      "print_high_quality"
    ]
  }
}
--customboundary--