NSUserDefaults or keychain is better to save username and password in iPhone app

Question

In my iphone app there is some confidential data like username, password and some urls to a webservice. Which one is better NSUserdefaults or keychain. Somebody says NSUser

Answer 1

It may be useful to notice that Keychain data will be persisted even if you app is deleted, but NSUserDefaults data will go away with the app (NSUserDefaults is part of the app sandbox, Keychain is an app-independent service).