This is a demo app for iOS data protection features and Keychain. It has some simple code samples on how to store various kinds of data, along with a very simple frontend that allows setting/reading items. It is meant as a companion to http://howtostoreiosdata.com/
You can use the simple frontend also to test the locking features, because for all data sets, there is also a button to retrieve the data after 12 seconds. If you tap that and quickly lock the phone, you'll see that retrieval of some data will now fail.