iphone - How to share keychain data between iOS applications

Question

I am describing a problem for which it took me quite some time to learn the answer.

The "GenericKeychain" example is a good start at providing a wrapper for sharing keychain data between applications when using the accessGroup in the init.

However, implementing this in my app yielded an obscure error code (which took forever to locate) -25243, which means: No access control.

I ran Apple's example app (GenericKeychain) on my iPad only to get the same error. Huh?

Does Apple's documentation fail to deliver on what is necessary to accomplish this?

Answer 1

After some (a lot of) digging throughout the web, I found the answer. The access Group that you use when constructing your KeychainItemWrapper class must ALSO be specified in each of your application's Entitlements.plist file in the "keychain-access-groups" section.

It seems almost obvious now that I see "keychain-access-groups". However, I had no idea to even look there. Hope this helps others.