Java

PDF Sign Unsigned Signature Field

See more PDF Signatures Examples

Demonstrates how to sign a PDF's unsigned signature field.

Note: This example requires Chilkat v9.5.0.85 or greater.

Chilkat2 Java

import com.chilkatsoft.chilkat2.Cert;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.JsonObject;
import com.chilkatsoft.chilkat2.Pdf;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        Pdf pdf = new Pdf();

        // Load a PDF containing an unsigned signature field.
        try {
            pdf.loadFile("qa_data/pdf/unsigned_sig_field/due_diligence.pdf");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // A PDF with an unsigned signature field appears in Adobe Acrobat as shown below.
        // (When the mouse pointer is hovered over the field, a tooltip will likely show a message
        // such as "Unsigned signature field (Click to sign)".
        // This example code will automatically find the unsigned signature field,
        // and signs using your certificate.  It automatically sizes the text to the space alotted
        // for the signature.
        // 

        // Options for signing are specified in JSON.
        JsonObject json = new JsonObject();

        // In most cases, the signingCertificateV2 and signingTime attributes are required.
        json.updateInt("signingCertificateV2", 1);
        json.updateInt("signingTime", 1);

        // We don't specify the page or a specific location because Chilkat will automatically
        // find the unsigned signature field and use its location and size and will scale the
        // signatures visual appearance (text + graphics) to the correct size required to fit.
        // We only need to indicate the desire to fill the unsigned signature field.
        json.updateBool("appearance.fillUnsignedSignatureField", true);

        // Starting in Chilkat v9.5.0.90, if a PDF contains multiple unsigned signature fields,
        // the field to be signed can be chosen by name:
        // To list unsigned signature fields, see this example: List PDF Unsigned Signature Fields
        json.updateString("unsignedSignatureField", "doctor_signature");

        // Note: If the PDF document contains multiple unsigned signature fields, Chilkat will
        // sign the 1st one found.

        // In this example, the appearance of the digital signature will contain three lines:
        // 1) The signing certificate's common name
        // 2) The current date/time
        // 3) Some arbitrary text.
        // The keyword "cert_cn" is replaced with the Certificate's Subject Common Name.
        // The keyword "current_dt" is replaced with the current date/time.
        // Any number of appearance text lines can be added.
        json.updateString("appearance.text[0]", "Digitally signed by: cert_cn");
        json.updateString("appearance.text[1]", "current_dt");
        json.updateString("appearance.text[2]", "The crazy brown fox jumps over the lazy dog.");

        // This signature will include one of the built-in SVG graphics (green-check-grey-circle).
        json.updateString("appearance.image", "green-check-grey-circle");
        json.updateString("appearance.imagePlacement", "left");

        // Load the signing certificate. (Use your own certificate.)
        Cert cert = new Cert();
        try {
            cert.loadPfxFile("qa_data/pfx/myPdfSigningCert.pfx", "secret");

            // Tell the pdf object to use the certificate for signing.
            pdf.setSigningCert(cert);

            pdf.signPdf(json, "qa_output/due_diligence_signed.pdf");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("The PDF has been successfully cryptographically signed.");

        // The appearance of the signature appears in Adobe Acrobat as shown below.
        // 
    }
}