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Add Password Protection to PDF using Java REST API

This tutorial shows how to PDF files can be secured with a password using Java and the Aspose PDF Cloud REST API. You’ll learn to protect a PDF document by setting user and owner passwords, choosing an encryption type, and defining allowed permissions, all through the Java SDK.

Prerequisite

Steps to Password Protect PDF Doc using Java REST Interface

  1. Import the required classes for Aspose PDF Cloud, file handling, and text encoding.
  2. Create a new PdfApi instance using your API key and App SID to authorize access to Aspose’s cloud services.
  3. Open your target PDF file from disk so you can read and process it.
  4. Convert your user and owner passwords into Base64 strings for secure transmission.
  5. Create a list of permissions—such as printing, extracting, and modifying content—that the encrypted PDF will allow.
  6. Call PutEncryptDocument to apply encryption to your file, specifying the output file name, encryption type, and the permissions list.
  7. After encryption, download the newly encrypted file from Aspose Cloud.
  8. Write the downloaded, encrypted content into a new file on your computer.

These steps summarize the process to protect a PDF document using the Java‑based API: import the necessary classes, instantiate PdfApi, open the PDF, set user and owner passwords, define allowed permissions, invoke PutEncryptDocument, then download and save the protected file. Print the response status to confirm success.

Code to Password Protect PDF Document using Java RESTful Service

The snippet demonstrates how to add a password to a PDF using the Java Low Code API. Remember to convert passwords to Base64 strings; otherwise, an exception will be thrown. You can also add more permissions such as ModifyTextAnnotations, FillForm, ExtractContentWithDisabilities, AssembleDocument, and PrintingQuality.

For information on verifying a signature in a PDF, see the article Verify signature in PDF using Java REST API.