title: What encryption algorithm does the iOS keychain use to protect data?
body: <p>After extensive googling I haven't managed to find an answer to this question<sup>1</sup>, which is surprising, since `security through obscurity' isn't really security at all...</p>
  
  <p>Is there a reliable source of an answer to this question (such as a certification application for iOS, source code, or similar)?</p>
  
  <p><sub><sup>1</sup>The only mention I could find was that it might use 3DES.</sub></p>