How to digitally sign pdf file

Question

Hi,
I am working on Java and Digital Signature and new to this field. I want to sign a pdf file using smart card. I have tried signing xml files and it's now running fine. The signature is attached with the xml file. Similarly I want to sign a pdf file and the signature should be attached with it.
Please help me to do that.
Thanks in advance.

Answer 1

Thnx.
Any way I could manage the matter.
I hope my code may help people working on same.
So the code is here
static String fname = "D:\\file.pdf";
static String fnameS = "D:\\file_signed.pdf";
//The main method
public static void main(String[] args) {
        try {
            this.signPdf() ;           
        } catch (Exception e) {
            System.out.println(e);
//The signer method
public static final boolean signPdf()
            throws IOException, DocumentException, Exception {
        String fileKey = "D:\\MyCertificate.pfx";
        String fileKeyPassword = "password";
        try {
            KeyStore ks = KeyStore.getInstance("pkcs12");
            ks.load(new FileInputStream(fileKey), fileKeyPassword.toCharArray());
            String alias = (String) ks.aliases().nextElement();
            PrivateKey key = (PrivateKey) ks.getKey(alias, fileKeyPassword.toCharArray());
            Certificate[] chain = ks.getCertificateChain(alias);
            PdfReader pdfReader = new PdfReader((new File(fname)).getAbsolutePath());
            File outputFile = new File(fnameS);
            PdfStamper pdfStamper;
            pdfStamper = PdfStamper.createSignature(pdfReader, null, '\0', outputFile);
            PdfSignatureAppearance sap = pdfStamper.getSignatureAppearance();
            //sap.setCrypto(key, chain, null, PdfSignatureAppearance.SELF_SIGNED);
            sap.setCrypto(key, chain, null, PdfSignatureAppearance.VERISIGN_SIGNED);
            sap.setReason("Security");
            sap.setLocation("Kolkata, India");
            sap.setSignDate(Calendar.getInstance());
            sap.setVisibleSignature(new Rectangle(10, 10, 50, 30), pdfReader.getNumberOfPages(), "Subhadip Pramanik");
            pdfStamper.setFormFlattening(true);
            pdfStamper.close();
            return true;
        } catch (Exception key) {
            throw new Exception(key);
    }