Java tutorial
/* * DSS - Digital Signature Services * * Copyright (C) 2011 European Commission, Directorate-General Internal Market and Services (DG MARKT), B-1049 Bruxelles/Brussel * * Developed by: 2011 ARHS Developments S.A. (rue Nicolas Bov 2B, L-1253 Luxembourg) http://www.arhs-developments.com * * This file is part of the "DSS - Digital Signature Services" project. * * "DSS - Digital Signature Services" is free software: you can redistribute it and/or modify it under the terms of * the GNU Lesser General Public License as published by the Free Software Foundation, either version 2.1 of the * License, or (at your option) any later version. * * DSS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License along with * "DSS - Digital Signature Services". If not, see <http://www.gnu.org/licenses/>. */ package eu.europa.ec.markt.dss.signature.pdf; import eu.europa.ec.markt.dss.signature.SignatureParameters; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.security.SignatureException; import java.security.cert.Certificate; import java.util.ArrayList; import java.util.Calendar; import java.util.HashMap; import java.util.List; import java.util.logging.Logger; import org.apache.commons.io.IOUtils; import com.lowagie.text.DocumentException; import com.lowagie.text.pdf.AcroFields; import com.lowagie.text.pdf.PdfDate; import com.lowagie.text.pdf.PdfDictionary; import com.lowagie.text.pdf.PdfName; import com.lowagie.text.pdf.PdfPKCS7; import com.lowagie.text.pdf.PdfReader; import com.lowagie.text.pdf.PdfSignature; import com.lowagie.text.pdf.PdfSignatureAppearance; import com.lowagie.text.pdf.PdfStamper; import com.lowagie.text.pdf.PdfString; /** * Implementation of PDFSignatureService using iText * * @version $Revision: 1867 $ - $Date: 2013-04-08 13:44:56 +0200 (Mon, 08 Apr 2013) $ */ public class ITextPDFDocTimeSampService implements PDFSignatureService { private static final Logger LOG = Logger.getLogger(ITextPDFDocTimeSampService.class.getName()); private int signatureSize = 12000; /** * @param signatureSize the signatureSize to set */ public void setSignatureSize(int signatureSize) { this.signatureSize = signatureSize; } /** * @return the signatureSize */ public int getSignatureSize() { return signatureSize; } @SuppressWarnings({ "unchecked", "rawtypes" }) private PdfStamper prepareStamper(InputStream pdfData, OutputStream output, SignatureParameters parameters) throws IOException, DocumentException { PdfReader reader = new PdfReader(pdfData); PdfStamper stp = PdfStamper.createSignature(reader, output, '\0', null, true); PdfSignatureAppearance sap = stp.getSignatureAppearance(); sap.setAcro6Layers(true); sap.setRender(PdfSignatureAppearance.SignatureRenderDescription); PdfSignature dic = new PdfSignature(PdfName.ADOBE_PPKLITE, new PdfName("ETSI.RFC3161")); // defined in ETSI TS 102 778-4 A.2 dic.put(PdfName.TYPE, new PdfName("DocTimeStamp")); Calendar cal = Calendar.getInstance(); if (parameters.getSigningDate() != null) { cal.setTime(parameters.getSigningDate()); sap.setSignDate(cal); } dic.setDate(new PdfDate(cal)); sap.setCryptoDictionary(dic); int csize = getSignatureSize(); HashMap exc = new HashMap(); exc.put(PdfName.CONTENTS, new Integer(csize * 2 + 2)); sap.preClose(exc); return stp; } @Override public byte[] digest(InputStream pdfData, SignatureParameters parameters) throws IOException, DocumentException { PdfStamper stp = prepareStamper(pdfData, new ByteArrayOutputStream(), parameters); PdfSignatureAppearance sap = stp.getSignatureAppearance(); MessageDigest md; try { md = MessageDigest.getInstance(parameters.getDigestAlgorithm().getName()); } catch (NoSuchAlgorithmException e) { throw new RuntimeException("No " + parameters.getDigestAlgorithm().getName() + " on this JRE!"); } InputStream s = sap.getRangeStream(); int read = 0; byte[] buff = new byte[8192]; while ((read = s.read(buff, 0, 8192)) > 0) { md.update(buff, 0, read); } byte[] digest = md.digest(); return digest; } @Override public void sign(InputStream pdfData, byte[] signatureValue, OutputStream signedStream, SignatureParameters parameters) throws IOException, DocumentException { PdfStamper stp = prepareStamper(pdfData, signedStream, parameters); PdfSignatureAppearance sap = stp.getSignatureAppearance(); byte[] pk = signatureValue; int csize = getSignatureSize(); byte[] outc = new byte[csize]; PdfDictionary dic2 = new PdfDictionary(); System.arraycopy(pk, 0, outc, 0, pk.length); dic2.put(PdfName.CONTENTS, new PdfString(outc).setHexWriting(true)); sap.close(dic2); } @Override public void validateSignatures(InputStream input, SignatureValidationCallback callback) throws IOException, SignatureException { validateSignatures(input, null, callback, new ArrayList<String>()); } @SuppressWarnings("unchecked") private void validateSignatures(InputStream input, PdfDictionary outerCatalog, SignatureValidationCallback callback, List<String> alreadyLoadedRevisions) throws IOException, SignatureException { PdfReader reader = new PdfReader(input); AcroFields af = reader.getAcroFields(); /* * Search the whole document of a signature */ ArrayList<String> names = af.getSignatureNames(); LOG.info(names.size() + " signature(s)"); // For every signature : for (String name : names) { // Affichage du nom LOG.info("Signature name: " + name); LOG.info("Signature covers whole document: " + af.signatureCoversWholeDocument(name)); // Affichage sur les revision - version LOG.info("Document revision: " + af.getRevision(name) + " of " + af.getTotalRevisions()); /* * We are only interrested in the validation of signature that covers the whole document. */ if (af.signatureCoversWholeDocument(name)) { PdfPKCS7 pk = af.verifySignature(name); Calendar cal = pk.getSignDate(); Certificate pkc[] = pk.getCertificates(); PdfDictionary signatureDictionary = af.getSignatureDictionary(name); String revisionName = Integer.toString(af.getRevision(name)); if (!alreadyLoadedRevisions.contains(revisionName)) { callback.validate(reader, outerCatalog, pk.getSigningCertificate(), cal != null ? cal.getTime() : null, pkc, signatureDictionary, pk); alreadyLoadedRevisions.add(revisionName); } } else { PdfDictionary catalog = reader.getCatalog(); /* * We open the version of the document that was protected by the signature */ ByteArrayOutputStream out = new ByteArrayOutputStream(); InputStream ip = af.extractRevision(name); IOUtils.copy(ip, out); out.close(); ip.close(); /* * You can sign a PDF document with only one signature. So when we want multiple signature, signatures * are appended sequentially to the end of the document. The recursive call help to get the signature * from the original document. */ validateSignatures(new ByteArrayInputStream(out.toByteArray()), catalog, callback, alreadyLoadedRevisions); } } } }