Encrypt and Decrypt PDF in Java

import java.util.EnumSet;

import com.spire.pdf.PdfDocument;
import com.spire.pdf.security.PdfEncryptionKeySize;
import com.spire.pdf.security.PdfPermissionsFlags;

public class EncryptPDF {

	public static void main(String[] args) {
		
        //Create a PdfDocument instance
        PdfDocument doc = new PdfDocument();
        //Load a PDF file
        doc.loadFromFile("input.pdf");

        //Encrypt the file
        PdfEncryptionKeySize keySize = PdfEncryptionKeySize.Key_128_Bit;
        String openPassword = "e-iceblue";
        String permissionPassword = "test";
        EnumSet flags = EnumSet.of(PdfPermissionsFlags.Print, PdfPermissionsFlags.Fill_Fields);
        doc.getSecurity().encrypt(openPassword, permissionPassword, flags, keySize);

        //Save and close
        doc.saveToFile("Encrypt.pdf");
        doc.close();		
      
	}

}

import com.spire.pdf.PdfDocument;
import com.spire.pdf.security.PdfEncryptionKeySize;
import com.spire.pdf.security.PdfPermissionsFlags;

public class DecryptPDF {

	public static void main(String[] args) throws Exception {
		
        //Create a PdfDocument instance
        PdfDocument doc = new PdfDocument();
        //Load the PDF file
        doc.loadFromFile("Encrypt.pdf", "test");

        //Decrypt the file
        doc.getSecurity().encrypt("", "", PdfPermissionsFlags.getDefaultPermissions(), PdfEncryptionKeySize.Key_256_Bit, "test");
        
        //Save and close
        doc.saveToFile("Decrypt.pdf");
        doc.close();
	}

}