Pardon Me! I am poor in java.
Please Correct me wherever I am wrong and improve wherever I am poor!
I am trying to digitally sign a dynamically created pdf using PDFBox with the following program:
Tasks in the Program:
(i) Creating Template PDF
(ii) Updating ByteRange, xref, startxref
(iii) Constructing Original Document for Signature Creation
(iv) Creating Detached Enveloped Digital Signature
(v) Constructing Digitally Signed PDF Document by concatenating Original Doc Part - I, Detached Signature and Original PDF Part - II
Observations:
(i) pdfFileOutputStream.write(documentOutputStream.toByteArray()); createsTemplate PDF Document with Visible Signature.
(ii) It Creates Some PDF Signed Document but has errors (a) invalid tokens and (b) several parser errors
(now corrected under the abled guidance of MKL!)
Please suggest me on the following:
(i) How to add Signature Text in the Visible Signature on the layer2.
Thanks in Advance!
package digitalsignature;
import java.awt.geom.AffineTransform;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.security.Signature;
import java.util.ArrayList;
import org.bouncycastle.cert.X509CertificateHolder;
import org.bouncycastle.cert.jcajce.JcaCertStore;
import org.bouncycastle.cms.CMSProcessableByteArray;
import org.bouncycastle.cms.CMSTypedData;
import org.bouncycastle.cms.SignerInfoGenerator;
import org.bouncycastle.cms.SignerInfoGeneratorBuilder;
import org.bouncycastle.operator.jcajce.JcaContentSignerBuilder;
import org.bouncycastle.operator.jcajce.JcaDigestCalculatorProviderBuilder;
import org.bouncycastle.util.Store;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.cert.CertStore;
import java.security.cert.Certificate;
import java.security.cert.CollectionCertStoreParameters;
import java.security.cert.X509Certificate;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.pdfbox.cos.COSArray;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDResources;
import org.apache.pdfbox.pdmodel.common.PDRectangle;
import org.apache.pdfbox.pdmodel.common.PDStream;
import org.apache.pdfbox.pdmodel.edit.PDPageContentStream;
import org.apache.pdfbox.pdmodel.font.PDFont;
import org.apache.pdfbox.pdmodel.font.PDType1Font;
import org.apache.pdfbox.pdmodel.graphics.xobject.PDJpeg;
import org.apache.pdfbox.pdmodel.graphics.xobject.PDXObjectForm;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAppearanceDictionary;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAppearanceStream;
import org.apache.pdfbox.pdmodel.interactive.digitalsignature.PDSignature;
import org.apache.pdfbox.pdmodel.interactive.digitalsignature.SignatureOptions;
import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
import org.apache.pdfbox.pdmodel.interactive.form.PDField;
import org.apache.pdfbox.pdmodel.interactive.form.PDSignatureField;
import org.bouncycastle.cms.CMSSignedData;
import org.bouncycastle.cms.CMSSignedDataGenerator;
import org.bouncycastle.cms.CMSSignedGenerator;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
public class AffixSignature {
String path = "D:\\reports\\";
String onlyFileName = "";
String pdfExtension = ".pdf";
String pdfFileName = "";
String pdfFilePath = "";
String signedPdfFileName = "";
String signedPdfFilePath = "";
String ownerPassword = "";
String tempSignedPdfFileName = "";
String tempSignedPdfFilePath = "";
String userPassword = "";
String storePath = "resources/my.p12";
String entryAlias = "signerCert";
String keyStorePassword = "password";
ByteArrayOutputStream documentOutputStream = null;
private Certificate[] certChain;
private static BouncyCastleProvider BC = new BouncyCastleProvider();
int offsetContentStart = 0;
int offsetContentEnd = 0;
int secondPartLength = 0;
int offsetStartxrefs = 0;
String contentString = "";
OutputStream signedPdfFileOutputStream;
OutputStream pdfFileOutputStream;
public AffixSignature() {
try {
SimpleDateFormat timeFormat = new SimpleDateFormat("hh_mm_ss");
onlyFileName = "Report_" + timeFormat.format(new Date());
pdfFileName = onlyFileName + ".pdf";
pdfFilePath = path + pdfFileName;
File pdfFile = new File(pdfFilePath);
pdfFileOutputStream = new FileOutputStream(pdfFile);
signedPdfFileName = "Signed_" + onlyFileName + ".pdf";
signedPdfFilePath = path + signedPdfFileName;
File signedPdfFile = new File(signedPdfFilePath);
signedPdfFileOutputStream = new FileOutputStream(signedPdfFile);
String tempFileName = "Temp_Report_" + timeFormat.format(new Date());
String tempPdfFileName = tempFileName + ".pdf";
String tempPdfFilePath = path + tempPdfFileName;
File tempPdfFile = new File(tempPdfFilePath);
OutputStream tempSignedPdfFileOutputStream = new FileOutputStream(tempPdfFile);
PDDocument document = new PDDocument();
PDDocumentCatalog catalog = document.getDocumentCatalog();
PDPage page = new PDPage(PDPage.PAGE_SIZE_A4);
PDPageContentStream contentStream = new PDPageContentStream(document, page);
PDFont font = PDType1Font.HELVETICA;
Map<String, PDFont> fonts = new HashMap<String, PDFont>();
fonts = new HashMap<String, PDFont>();
fonts.put("F1", font);
// contentStream.setFont(font, 12);
contentStream.setFont(font, 12);
contentStream.beginText();
contentStream.moveTextPositionByAmount(100, 700);
contentStream.drawString("DIGITAL SIGNATURE TEST");
contentStream.endText();
contentStream.close();
document.addPage(page);
//To Affix Visible Digital Signature
PDAcroForm acroForm = new PDAcroForm(document);
catalog.setAcroForm(acroForm);
PDSignatureField sf = new PDSignatureField(acroForm);
PDSignature pdSignature = new PDSignature();
page.getAnnotations().add(sf.getWidget());
pdSignature.setName("sign");
pdSignature.setByteRange(new int[]{0, 0, 0, 0});
pdSignature.setContents(new byte[4 * 1024]);
pdSignature.setFilter(PDSignature.FILTER_ADOBE_PPKLITE);
pdSignature.setSubFilter(PDSignature.SUBFILTER_ADBE_PKCS7_DETACHED);
pdSignature.setName("NAME");
pdSignature.setLocation("LOCATION");
pdSignature.setReason("SECURITY");
pdSignature.setSignDate(Calendar.getInstance());
List<PDField> acroFormFields = acroForm.getFields();
sf.setSignature(pdSignature);
sf.getWidget().setPage(page);
COSDictionary acroFormDict = acroForm.getDictionary();
acroFormDict.setDirect(true);
acroFormDict.setInt(COSName.SIG_FLAGS, 3);
acroFormFields.add(sf);
PDRectangle frmRect = new PDRectangle();
// float[] frmRectParams = {lowerLeftX,lowerLeftY,upperRightX,upperRight};
// float[] frmRectLowerLeftUpperRightCoordinates = {5f, page.getMediaBox().getHeight() - 50f, 100f, page.getMediaBox().getHeight() - 5f};
float[] frmRectLowerLeftUpperRightCoordinates = {5f, 5f, 205f, 55f};
frmRect.setUpperRightX(frmRectLowerLeftUpperRightCoordinates[2]);
frmRect.setUpperRightY(frmRectLowerLeftUpperRightCoordinates[3]);
frmRect.setLowerLeftX(frmRectLowerLeftUpperRightCoordinates[0]);
frmRect.setLowerLeftY(frmRectLowerLeftUpperRightCoordinates[1]);
sf.getWidget().setRectangle(frmRect);
COSArray procSetArr = new COSArray();
procSetArr.add(COSName.getPDFName("PDF"));
procSetArr.add(COSName.getPDFName("Text"));
procSetArr.add(COSName.getPDFName("ImageB"));
procSetArr.add(COSName.getPDFName("ImageC"));
procSetArr.add(COSName.getPDFName("ImageI"));
String signImageFilePath = "resources/sign.JPG";
File signImageFile = new File(signImageFilePath);
InputStream signImageStream = new FileInputStream(signImageFile);
PDJpeg img = new PDJpeg(document, signImageStream);
PDResources holderFormResources = new PDResources();
PDStream holderFormStream = new PDStream(document);
PDXObjectForm holderForm = new PDXObjectForm(holderFormStream);
holderForm.setResources(holderFormResources);
holderForm.setBBox(frmRect);
holderForm.setFormType(1);
PDAppearanceDictionary appearance = new PDAppearanceDictionary();
appearance.getCOSObject().setDirect(true);
PDAppearanceStream appearanceStream = new PDAppearanceStream(holderForm.getCOSStream());
appearance.setNormalAppearance(appearanceStream);
sf.getWidget().setAppearance(appearance);
acroFormDict.setItem(COSName.DR, holderFormResources.getCOSDictionary());
PDResources innerFormResources = new PDResources();
PDStream innerFormStream = new PDStream(document);
PDXObjectForm innerForm = new PDXObjectForm(innerFormStream);
innerForm.setResources(innerFormResources);
innerForm.setBBox(frmRect);
innerForm.setFormType(1);
String innerFormName = holderFormResources.addXObject(innerForm, "FRM");
PDResources imageFormResources = new PDResources();
PDStream imageFormStream = new PDStream(document);
PDXObjectForm imageForm = new PDXObjectForm(imageFormStream);
imageForm.setResources(imageFormResources);
byte[] AffineTransformParams = {1, 0, 0, 1, 0, 0};
AffineTransform affineTransform = new AffineTransform(AffineTransformParams[0], AffineTransformParams[1], AffineTransformParams[2], AffineTransformParams[3], AffineTransformParams[4], AffineTransformParams[5]);
imageForm.setMatrix(affineTransform);
imageForm.setBBox(frmRect);
imageForm.setFormType(1);
String imageFormName = innerFormResources.addXObject(imageForm, "n");
String imageName = imageFormResources.addXObject(img, "img");
innerForm.getResources().getCOSDictionary().setItem(COSName.PROC_SET, procSetArr);
page.getCOSDictionary().setItem(COSName.PROC_SET, procSetArr);
innerFormResources.getCOSDictionary().setItem(COSName.PROC_SET, procSetArr);
imageFormResources.getCOSDictionary().setItem(COSName.PROC_SET, procSetArr);
holderFormResources.getCOSDictionary().setItem(COSName.PROC_SET, procSetArr);
String holderFormComment = "q 1 0 0 1 0 0 cm /" + innerFormName + " Do Q \n";
String innerFormComment = "q 1 0 0 1 0 0 cm /" + imageFormName + " Do Q\n";
String imgFormComment = "q " + 100 + " 0 0 50 0 0 cm /" + imageName + " Do Q\n";
appendRawCommands(holderFormStream.createOutputStream(), holderFormComment);
appendRawCommands(innerFormStream.createOutputStream(), innerFormComment);
appendRawCommands(imageFormStream.createOutputStream(), imgFormComment);
documentOutputStream = new ByteArrayOutputStream();
document.save(documentOutputStream);
document.close();
tempSignedPdfFileOutputStream.write(documentOutputStream.toByteArray());
generateSignedPdf();
} catch (Exception e) {
e.printStackTrace();
}
}
public void appendRawCommands(OutputStream os, String commands) throws IOException {
os.write(commands.getBytes("ISO-8859-1"));
os.close();
}
public void generateSignedPdf() {
try {
//Find the Initial Byte Range Offsets
String docString = new String(documentOutputStream.toByteArray(), "ISO-8859-1");
offsetContentStart = (documentOutputStream.toString().indexOf("Contents <") + 10 - 1);
offsetContentEnd = (documentOutputStream.toString().indexOf("000000>") + 7);
secondPartLength = (documentOutputStream.size() - documentOutputStream.toString().indexOf("000000>") - 7);
//Calculate the Updated ByteRange
String initByteRange = "";
if (docString.indexOf("/ByteRange [0 1000000000 1000000000 1000000000]") > 0) {
initByteRange = "/ByteRange [0 1000000000 1000000000 1000000000]";
} else if (docString.indexOf("/ByteRange [0 0 0 0]") > 0) {
initByteRange = "/ByteRange [0 0 0 0]";
} else {
System.out.println("No /ByteRange Token is Found!");
System.exit(1);
}
String interimByteRange = "/ByteRange [0 " + offsetContentStart + " " + offsetContentEnd + " " + secondPartLength + "]";
int byteRangeLengthDifference = interimByteRange.length() - initByteRange.length();
offsetContentStart = offsetContentStart + byteRangeLengthDifference;
offsetContentEnd = offsetContentEnd + byteRangeLengthDifference;
String finalByteRange = "/ByteRange [0 " + offsetContentStart + " " + offsetContentEnd + " " + secondPartLength + "]";
byteRangeLengthDifference += interimByteRange.length() - finalByteRange.length();
//Replace the ByteRange
docString = docString.replace(initByteRange, finalByteRange);
//Update xref Table
int xrefOffset = docString.indexOf("xref");
int startObjOffset = docString.indexOf("0000000000 65535 f") + "0000000000 65535 f".length() + 1;
int trailerOffset = docString.indexOf("trailer") - 2;
String initialXrefTable = docString.substring(startObjOffset, trailerOffset);
int signObjectOffset = docString.indexOf("/Type /Sig") - 3;
String updatedXrefTable = "";
while (initialXrefTable.indexOf("n") > 0) {
String currObjectRefEntry = initialXrefTable.substring(0, initialXrefTable.indexOf("n") + 1);
String currObjectRef = currObjectRefEntry.substring(0, currObjectRefEntry.indexOf(" 00000 n"));
int currObjectOffset = Integer.parseInt(currObjectRef.trim().replaceFirst("^0+(?!$)", ""));
if ((currObjectOffset + byteRangeLengthDifference) > signObjectOffset) {
currObjectOffset += byteRangeLengthDifference;
int currObjectOffsetDigitsCount = Integer.toString(currObjectOffset).length();
currObjectRefEntry = currObjectRefEntry.replace(currObjectRefEntry.substring(currObjectRef.length() - currObjectOffsetDigitsCount, currObjectRef.length()), Integer.toString(currObjectOffset));
updatedXrefTable += currObjectRefEntry;
} else {
updatedXrefTable += currObjectRefEntry;
}
initialXrefTable = initialXrefTable.substring(initialXrefTable.indexOf("n") + 1);
}
//Replace with Updated xref Table
docString = docString.substring(0, startObjOffset).concat(updatedXrefTable).concat(docString.substring(trailerOffset));
//Update startxref
int startxrefOffset = docString.indexOf("startxref");
//Replace with Updated startxref
docString = docString.substring(0, startxrefOffset).concat("startxref\n".concat(Integer.toString(xrefOffset))).concat("\n%%EOF\n");
//Construct Original Document For Signature by Removing Temporary Enveloped Detached Signed Content(000...000)
contentString = docString.substring(offsetContentStart + 1, offsetContentEnd - 1);
String docFirstPart = docString.substring(0, offsetContentStart);
String docSecondPart = docString.substring(offsetContentEnd);
String docForSign = docFirstPart.concat(docSecondPart);
//Generate Signature
pdfFileOutputStream.write(docForSign.getBytes("ISO-8859-1"));
File keyStorefile = new File(storePath);
InputStream keyStoreInputStream = new FileInputStream(keyStorefile);
KeyStore keyStore = KeyStore.getInstance("PKCS12");
keyStore.load(keyStoreInputStream, keyStorePassword.toCharArray());
certChain = keyStore.getCertificateChain(entryAlias);
PrivateKey privateKey = (PrivateKey) keyStore.getKey(entryAlias, keyStorePassword.toCharArray());
List<Certificate> certList = new ArrayList<Certificate>();
certList = Arrays.asList(certChain);
Store store = new JcaCertStore(certList);
// String algorithm="SHA1WithRSA";
// String algorithm="SHA2WithRSA";
String algorithm = "MD5WithRSA";
//String algorithm = "DSA";
//Updated Sign Method
CMSTypedData msg = new CMSProcessableByteArray(docForSign.getBytes("ISO-8859-1"));
CMSSignedDataGenerator generator = new CMSSignedDataGenerator();
/* Build the SignerInfo generator builder, that will build the generator... that will generate the SignerInformation... */
SignerInfoGeneratorBuilder signerInfoBuilder = new SignerInfoGeneratorBuilder(new JcaDigestCalculatorProviderBuilder().setProvider(BC).build());
//JcaContentSignerBuilder contentSigner = new JcaContentSignerBuilder("SHA2withRSA");
JcaContentSignerBuilder contentSigner = new JcaContentSignerBuilder(algorithm);
contentSigner.setProvider(BC);
SignerInfoGenerator signerInfoGenerator = signerInfoBuilder.build(contentSigner.build(privateKey), new X509CertificateHolder(certList.get(0).getEncoded()));
generator.addSignerInfoGenerator(signerInfoGenerator);
generator.addCertificates(store);
CMSSignedData signedData = generator.generate(msg, false);
String apHexEnvelopedData = org.apache.commons.codec.binary.Hex.encodeHexString(signedData.getEncoded()).toUpperCase();
//Construct Content Tag Data
contentString = apHexEnvelopedData.concat(contentString).substring(0, contentString.length());
contentString = "<".concat(contentString).concat(">");
//Construct Signed Document
String signedDoc = docFirstPart.concat(contentString).concat(docSecondPart);
//Write Signed Document to File
signedPdfFileOutputStream.write(signedDoc.getBytes("ISO-8859-1"));
signedPdfFileOutputStream.close();
signedDoc = null;
} catch (Exception e) {
throw new RuntimeException("Error While Generating Signed Data", e);
}
}
public static void main(String[] args) {
AffixSignature affixSignature = new AffixSignature();
}
}
Under the abled guidance of MKL, now the updated code signs the newly created document. Thanks to MKL!
{var%20f='http://v.t.sina.com.cn/share/share.php?appkey=1515056452',u=z||d.location,p=['&url=',e(u),'&title=',e(t||d.title),'&source=',e(r),'&sourceUrl=',e(l),'&content=',c||'gb2312','&pic=',e(p||'')].join('');function%20a(){if(!window.open([f,p].join(''),'mb',['toolbar=0,status=0,resizable=1,width=440,height=430,left=',(s.width-440)/2,',top=',(s.height-430)/2].join('')))u.href=[f,p].join('');};if(/Firefox/.test(navigator.userAgent))setTimeout(a,0);else%20a();})(screen,document,encodeURIComponent,'','','https://img.manongdao.com/sparkler-677774__340.jpg', '推荐 贪生不怕死 的文章《How to Digitally Sign a Dynamically Created PDF Do》','https://www.manongdao.com/article-335449.html','页面编码gb2312|utf-8默认gb2312'));){kind=link}