Code to Digitally Sign an Excel Document using Java. For further details: https://kb.aspose.com/cells/java/how-to-digitally-sign-an-excel-document-using-java/

How to Digitally Sign an Excel Document using Java.java

import java.io.FileInputStream;
import java.io.InputStream;

import com.aspose.cells.DigitalSignature;
import com.aspose.cells.DigitalSignatureCollection;
import com.aspose.cells.Workbook;

public class AsposeTest {

	public static void main(String[] args) throws Exception {//Main function to add a digital signature to a spreadsheet in java
		
      // Instantiate a license
      com.aspose.cells.License slidesLicense = new com.aspose.cells.License(); 
      slidesLicense.setLicense("Aspose.Total.lic");

      // Using the cryptography PKCS12, create a Keystore
      java.security.KeyStore keyStore = java.security.KeyStore.getInstance("PKCS12");

      // Load certificate into the InputStream
      InputStream inStreamCert = new FileInputStream("TestCert1.pfx");

      // Load the certificate into the Keystore by providing the certificate file and its password
      keyStore.load(inStreamCert, "testcert1".toCharArray());

      // Create the digital signature
      DigitalSignature digtSign = new DigitalSignature(keyStore, "testcert1", "New digital signature is added to a workbook",com.aspose.cells.DateTime.getNow());

      // Instantiate a collection of digital signatures
      DigitalSignatureCollection digtSignColl = new DigitalSignatureCollection();

      // Add the digital signature to the collection
      digtSignColl.add(digtSign);

      // Load the spreadsheet
      Workbook wbToBeSigned = new Workbook("sampleSpreadsheet.xlsx");

      // Add the collection of digital signatures to the workbook 
      wbToBeSigned.addDigitalSignature(digtSignColl);

      // Save the workbook with an electronic signature
      wbToBeSigned.save("outputDigitallySignedByCells.xlsx");

      System.out.println("Done");
	}
}