Will elements in the iOS keychain survive the removal and reinstallation of the application?

Question

I am looking for documentation on iOS keychain elements. My specific question is that the keychain elements will withstand the removal of the application and the reinstallation of the loop. This seems to work with iOS 4 (or maybe even iOS 3), but I can't find Apple's documentation stating that it should actually work that way.

What I'm trying to understand is if I can TRUST (not "hope for" or "guess") that the elements in the keychain will survive the removal of the application.

EDIT: I understand the question is a bit unclear, as Dai-jan pointed out. I am looking for official documentation that supports well-known behavior.

UPDATE 2017-04-04: see my answer below, behavior change in iOS 10.3 beta. It works as usual in iOS 10.3, but is likely to change in future versions.

Answer 1

I dug in the Apple developer forums, and the Apple developer (eskimo1, aka Quinn) states in 2012-08-27 that this is current behavior, but this is far from the way he does not know / documented / behavior, so this may change in the future . He also says that removing common keychain elements will always be difficult, which is one of the reasons it has not yet been considered.

So, I think this leaves the question open: there is no final answer. It is not documented and can change at any time. Relying on this MAY create problems in the future.

UPDATE 2017-04-04:

In iOS 10.3, beta keychain information for an application is deleted when the application is deleted, but this behavior seems to have been removed in the latest version 10.3. The Apple Documentation assumes this is about to change, and we should not rely on keychain access data that remains intact after uninstalling the application. See Also iOS 10.3 beta 3 does not save KeychainItem data .

Answer 2

Perhaps this is what you are looking for.
Apple Documentation

Note. On iPhone, keyring rights depend on the provisioning profile that is used to sign your application. Be sure to consistently use the same security profile across different versions of your application.

Answer 3

yes they will.

see my corresponding question:

How to know WHEN a user first bought an application / installed it (perhaps without a UDID?)

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HOW DO I SEE THIS:

"Officially" this is implied by the fact that the keychain is for several applications .. and that it "belongs" to os:

Apple Documentation

A keychain is an encrypted container that contains passwords for several applications and secure services.

=> ergo keychain survives the application

a plus

keychain can be shared among several applications