textmode password field blank when using wizard

The Textbox's Text Mode is password when using it in Wizard or Multiview the text values will get clear while moving to another view or wizard, So in like that situation we go to ViewState or Session,Dont go for hidden Field cause we can see hidden field values in View Source,so its not secure.

ViewState["mypass"] = txtPassword.Text;
Multiview1.ActiveViewIndex =1;