When are iOS keychain items removed?

Question

I could have sworn this worked differently in previous versions of iOS, but as of iOS 4.0 it looks like my app's keychain items are not removed when the app is removed. However, it looks like some are cleared when the app is upgraded without first removing?

Can someone provide a clear explanation of when iOS keychain items are removed?

Answer 1

As answered here, and somewhere else (I can't remember where I read it), the keychain will persist even after the app is removed. I am almost positive that the keychain isn't cleared unless you explicitly delete an item in it.

Answer 2

If you do a secure wipe of the device, then you may get a fresh keychain.