C# WInforn config file database password encription while saving the file

  we created service for that database connection created through config file. presently
   database name , username and password showing in one text box without encript the password
   what i want to do now, i want to encript the password in the config file while saving it password shoud be
   encript and i dont want to change password also. In c# winform config file how to do the above problem.can anybody help