Add and Delete Digital Signature in Excel in Java

import com.spire.xls.*;
import com.spire.xls.digital.CertificateAndPrivateKey;

import java.util.Date;


public class AddDigitalSignature {
    public static void main(String[] args) throws Exception {
        //Load the sample document
        Workbook workbook=new Workbook();
        workbook.loadFromFile("Sample.xlsx");

        //Add digital signature
        CertificateAndPrivateKey cap = new CertificateAndPrivateKey("Test.pfx","e-iceblue");
        workbook.addDigitalSignature(cap, "e-iceblue",new Date());

        //Save the document
        String result="AddDigitalSignature.xlsx";
        workbook.saveToFile(result,ExcelVersion.Version2013);

    }
}

import com.spire.xls.*;

public class RemoveDigitalSignature {
    public static void main(String[] args) throws Exception {
        //Load the sample document
        Workbook workbook=new Workbook();
        workbook.loadFromFile("AddDigitalSignature.xlsx");

        //Remove digital signature
        workbook.removeAllDigitalSignatures();

        //Save the document 
        String result="RemoveDigitalSignature.xlsx";
        workbook.saveToFile(result,ExcelVersion.Version2013);

    }
}