Apply a digital signature to a PDF using a custom image appearance

This Java sample code applies a digital signature to a document with a custom appearance. The appearance of signatures can be modified in jPDFSecure to include an image, choose the fields that show or custom text.

/**
 * Qoppa Software - Sample Source Code
 */
package jPDFSecureSamples;
 
import java.awt.geom.Rectangle2D;
import java.io.FileInputStream;
import java.security.KeyStore;
 
import javax.swing.SwingConstants;
 
import com.qoppa.pdf.SignatureAppearance;
import com.qoppa.pdf.SigningInformation;
import com.qoppa.pdf.form.SignatureField;
import com.qoppa.pdfSecure.PDFSecure;
 
public class CustomSignature
{
 
    public static void main (String [] args)
    {
        try
        {
            // Load the document
            PDFSecure pdfDoc = new PDFSecure ("input.pdf", null);
 
            // Load the keystore that contains the digital id to use in signing
            FileInputStream pkcs12Stream = new FileInputStream ("keystore.pfx");
            KeyStore store = KeyStore.getInstance("PKCS12");
            store.load(pkcs12Stream, "store_pwd".toCharArray());
            pkcs12Stream.close();
 
            // Create signing information
            SigningInformation signInfo = new SigningInformation (store, "key_alias", "key_pwd");
 
            // Set signing properties that will be saved in the signature
            signInfo.setContactInformation("Phone:404-685-8733");
            signInfo.setReason("I approve this document");
            signInfo.setLocation("Atlanta, GA");
 
            // Customize the signature appearance
            SignatureAppearance signAppear = signInfo.getSignatureAppearance();
 
            // LEFT SIDE OF SIGNATURE APPEARANCE
            // Show an image of handwrittern signature, left justified
            signAppear.setImagePosition(SwingConstants.LEFT);
            signAppear.setImageFile("signature.jpg");
            // Show visible name which is located on the left side
            signAppear.setVisibleName(false);
 
            // RIGHT SIDE OF SIGNATURE APPEARANCE
            // Show Digitally Signed By and Date 
            signAppear.setVisibleDigitallySigned(true);
            signAppear.setVisibleDate(true);
            // Hide all other fields that usually show on the right side
            signAppear.setVisibleCommonName(false);
            signAppear.setVisibleOrgUnit(false);
            signAppear.setVisibleOrgName(false);
            signAppear.setVisibleLocal(false);
            signAppear.setVisibleState(false);
            signAppear.setVisibleCountry(false);
            signAppear.setVisibleEmail(false);
 
            // Create signature field on the first page
            Rectangle2D signBounds = new Rectangle2D.Double (36, 36, 144, 48);
            SignatureField signField = pdfDoc.addSignatureField(0, "signature", signBounds);
 
            // Apply digital signature
            pdfDoc.signDocument(signField, signInfo);
 
            // Save the document
            pdfDoc.saveDocument ("output.pdf");
        }
        catch (Throwable t)
        {
            t.printStackTrace();
        }
    }
 
}
signature_custom1
In this custom signature appearance, we’ve added a picture of a handwritten signature while keeping the visible name on the left side and “Digitally signed by” with the date on the right side.