I am developing an iOS app that it has to store username and password and other sensitive data. I am considering using NSUserDefaults or keychain storage. Are there other more secure method to keep attackers from defeating iOS keychain or such data protection?
There's a good read-up on this whole security topic here, it's an older article but anyway. I personally think that the whole security concept on apples iOS platform together with hardware encryption on iOS devices is really good. Android and Android devices are problematic as we all know.
But adding additional security measures, by encrypting your data additionally, is not a bad idea anyway!