com.aspose.words

Example:

Document doc = new Document();
DocumentBuilder builder = new DocumentBuilder(doc);

builder.writeln("Hello world!");

PdfEncryptionDetails encryptionDetails =
        new PdfEncryptionDetails("password", "", PdfEncryptionAlgorithm.RC_4_128);

// Start by disallowing all permissions.
encryptionDetails.setPermissions(PdfPermissions.DISALLOW_ALL);

// Extend permissions to allow the editing of annotations.
encryptionDetails.setPermissions(PdfPermissions.MODIFY_ANNOTATIONS | PdfPermissions.DOCUMENT_ASSEMBLY);

// Create a "PdfSaveOptions" object that we can pass to the document's "Save" method
// to modify how that method converts the document to .PDF.
PdfSaveOptions saveOptions = new PdfSaveOptions();

// Enable encryption via the "EncryptionDetails" property.
saveOptions.setEncryptionDetails(encryptionDetails);

// When we open this document, we will need to provide the password before accessing its contents.
doc.save(getArtifactsDir() + "PdfSaveOptions.EncryptionPermissions.pdf", saveOptions);