How to create zip file in C#.NET with secured password?

using System.IO;
using Ionic.Zip;

namespace ArchieveFiles
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }        
        private void btnOpen1_Click(object sender, EventArgs e)
        {
            OpenFileDialog fDialog = new OpenFileDialog();
            fDialog.Title = "Select file to be zip";
            //fDialog.Filter = "JPEG Files|*.jpeg|GIF Files|*.gif";
            if (fDialog.ShowDialog() == DialogResult.OK)
            {
                textBox1.Text = fDialog.FileName.ToString();
            }
        }

        private void btnZip1_Click(object sender, EventArgs e)
        {
            if (textBox1.Text == "")
            {
                MessageBox.Show("select file to be Zip","Alert");
                return;
            }         

            SaveFileDialog saveFileDialog1 = new SaveFileDialog();
            saveFileDialog1.Filter = "zip files (*.zip)|*.zip|rar files (*.rar)|*.rar";
            saveFileDialog1.FilterIndex = 2;
            saveFileDialog1.RestoreDirectory = true;

            if (saveFileDialog1.ShowDialog() == DialogResult.OK)
            {
                //Zip one file
                string filename = textBox1.Text;

                try
                {
                    /*** ZIP Single file - START HERE */

                    using (var zip = new ZipFile())
                    {
                        //Set password for your zip file
                        zip.Password = "test123"; 
                        zip.AddFile(filename,"");                        
                        zip.Save(saveFileDialog1.FileName.ToString());
                    }

                    // extract entries that use encryption
                    using (ZipFile zip = ZipFile.Read(saveFileDialog1.FileName.ToString()))
                    {
                        //check password before file is extract
                        zip.Password = "test123";
                        zip.ExtractAll("extractDir");

                    }
                    /*** ZIP Single file - END HERE */
                    MessageBox.Show("Files are Zipped Successfully!", "Alert");
                }
                catch (Exception ex)
                {
                    MessageBox.Show("Error during Zip operation!", "Alert");
                }
                clear();
            }         
        }

        private void btnOpen2_Click(object sender, EventArgs e)
        {
            //Open Folder Browser Dialog 

            FolderBrowserDialog FBDialog = new FolderBrowserDialog(); 
            {

                FBDialog.RootFolder = Environment.SpecialFolder.Desktop;
                FBDialog.SelectedPath = "c:\\windows";               
                FBDialog.Description = "Select the directory to save Zip";
                if (FBDialog.ShowDialog() == DialogResult.OK)
                {
                    textBox2.Text = FBDialog.SelectedPath;
                }
            }
        }

        private void btnZip2_Click(object sender, EventArgs e)
        {
            if (textBox2.Text == "")
            {
                MessageBox.Show("select folder to be Zip","Alert");
                return;
            }

            SaveFileDialog saveFileDialog2 = new SaveFileDialog();

            saveFileDialog2.Filter = "zip files (*.zip)|*.zip|rar files (*.rar)|*.rar";
            saveFileDialog2.FilterIndex = 2;
            saveFileDialog2.RestoreDirectory = true;

            if (saveFileDialog2.ShowDialog() == DialogResult.OK)
            {
                //Zip directory including all files
                string filename = textBox1.Text;
                try
                {                 

                    using (var zip = new ZipFile())
                    {
                        zip.AddDirectory(textBox2.Text,"");
                        zip.Save(saveFileDialog2.FileName.ToString());
                    }                  
                    MessageBox.Show("Files are Zipped Successfully!", "Alert");
                }
                catch (Exception ex)
                {
                    MessageBox.Show("Error during Zip operation!", "Alert");
                }
                clear();
            }        
        }

        private void btnOpen3_Click(object sender, EventArgs e)
        {
            //Open Folder Browser Dialog 

            FolderBrowserDialog FBDialog = new FolderBrowserDialog();
            {

                FBDialog.RootFolder = Environment.SpecialFolder.Desktop;
                FBDialog.SelectedPath = "c:\\windows";
                FBDialog.Description = "Select the directory to save Zip";
                if (FBDialog.ShowDialog() == DialogResult.OK)
                {
                    textBox3.Text = FBDialog.SelectedPath;
                }
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {


            if (textBox3.Text == "")
            {
                MessageBox.Show("select file to be Zip", "Alert");
                return;
            }
          

            /*** ZIP Multiple .jpg file - START HERE */

            //Metion your File Path here 
            string path = textBox3.Text;

            SaveFileDialog saveFileDialog3 = new SaveFileDialog();
            saveFileDialog3.Filter = "zip files (*.zip)|*.zip|rar files (*.rar)|*.rar";
            saveFileDialog3.FilterIndex = 2;
            saveFileDialog3.RestoreDirectory = true;

            if (saveFileDialog3.ShowDialog() == DialogResult.OK)
            {
                //Zip directory including all files
                string filename = textBox1.Text;

                try
                {
                     DirectoryInfo datafile = new DirectoryInfo(path);
                     FileInfo[] arfiles = datafile.GetFiles("*.*");
                     FileInfo finfo = default(FileInfo);

                    if (System.IO.Directory.Exists(path))
                    {
                        using (var zip = new ZipFile())
                        {
                            for (int i = 0; i <= arfiles.Length - 1; i++)
                            {
                                //Read Each files and ZIP it and check jog files

                                if (arfiles.Length > 0)
                                {
                                    finfo = arfiles[i];
                                    if (finfo.Extension == ".jpg")
                                    {
                                        zip.AddFile(finfo.FullName,"");
                                    }
                                }
                            }                    
                            zip.Save(saveFileDialog3.FileName.ToString());
                        }
                        MessageBox.Show("Files are Zipped Successfully!", "Alert");
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show("Error during Zip operation!", "Alert");
                }
                clear();
            }  
            /*** ZIP Multiple file - END HERE */            
        }
        void clear()
        {
            textBox1.Text = "";
            textBox2.Text = "";
            textBox3.Text = "";
        }

        private void label6_Click(object sender, EventArgs e)
        {

        }          
    }
}