title: security of NSUserDefaults in Swift
body: <p>I'm working with one of my first iPhone apps. I have made simple login for the users. I want to store variable in NSUserDefaults which will keep track of if user is logged in. If user is logged in than it will be 1, otherwise it will be 0. And of course in other variable user username.</p>
  
  <p>My question is: Is NSUserDefaults secure for keeping information like that? Is there any way in which somebody or user could manipulate with this variables and login without knowing password?</p>