The [iOS Keychain Services Programming Guide] (https://developer.apple.com/library/ios/documentation/Security/Conceptual/keychainServConcepts/iPhoneTasks/iPhoneTasks.html) is a little outdated. The [GenericKeychain sample app] (https://developer.apple.com/library/ios/samplecode/GenericKeychain/Introduction/Intro.html#//apple_ref/doc/uid/DTS40007797) it references was last edited in July 2010. It contains sample code that has not been migrated to ARC. I found it a little difficult to understand, so I migrated the code to ARC and used it in a sample app.

The comments in the my KeychainItemWrapper.m match Apple's comments in their sample Classes/KeychainItemWrapper.m.