In various cases, PDF documents are encrypted before they are shared among the stakeholders. The encryption makes the document secure from unauthorized access as well as the content tampering. There are a couple of popular ways of securing the PDF documents – encrypting PDF with a password or limiting the user’s access permissions such as printing, editing, copying, etc. This article demonstrates how to encrypt or decrypt a PDF document using Java. In addition, you will learn how to limit the user’s privileges in a PDF document.