Encryption and Metadata

Reading an encrypted PDF

const pdfDoc = await PDFDocument.load(bytes, { password: 'secret' });

Without the password, loading throws EncryptedPDFError. To inspect a document without decrypting it:

const pdfDoc = await PDFDocument.load(bytes, { ignoreEncryption: true });

Content read this way will be ciphertext, so this is only useful for structural inspection.

Encrypting output

const bytes = await pdfDoc.save({
  userPassword: 'open-me',
  ownerPassword: 'owner',
  permissions: {
    printing: 'highResolution',
    modifying: false,
    copying: false,
  },
});

What PDF permissions actually do

Permissions are advisory. A conforming reader honours them; nothing forces one to. Treat them as a statement of intent, not a security control — if content must not be copied, do not put it in the file.

Metadata

pdfDoc.setTitle('Quarterly Report');
pdfDoc.setAuthor('Sokha Chan');
pdfDoc.setSubject('Financial results');
pdfDoc.setKeywords(['report', 'q3', 'finance']);
pdfDoc.setProducer('HappyPDF');
pdfDoc.setCreator('reporting-service');
pdfDoc.setCreationDate(new Date('2026-01-01'));
pdfDoc.setModificationDate(new Date());

Reading it back:

pdfDoc.getTitle();
pdfDoc.getAuthor();
pdfDoc.getCreationDate();

Reproducible output

Documents get a creation and modification date by default, so saving the same input twice produces different bytes. To make output byte-identical:

const pdfDoc = await PDFDocument.create({ updateMetadata: false });

Useful for content-addressed storage, caching, and for tests that compare output.

Viewer preferences

const prefs = pdfDoc.catalog.getOrCreateViewerPreferences();
prefs.setDisplayDocTitle(true);
prefs.setHideToolbar(false);

PDF/A

import { convertToPDFA3 } from 'happypdf';

await convertToPDFA3(pdfDoc, { conformance: 'B' });

PDF/A requires every font to be embedded — which HappyPDF does for custom fonts — and disallows encryption. The standard 14 fonts are not embedded and are therefore not PDF/A compliant, so embed a real font for archival output.