Storing keys in KeyChain with KeyChainItemWrapper

问题:

I'm using KeyChainItemWrapper class, provided by Apple's Sample Code to save the authentication token to the keychain.

KeychainItemWrapper *keychain = [[KeychainItemWrapper alloc] initWithIdentifier"JetTaxiApp_AuthToken" accessGroup:nil];  

But when I'm trying to set the value to keychain, an odd exception is raised

[_authenticationTokenKeychain setObject:authenticationToken forKey: @"auth_token"];

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Couldn't add the Keychain Item.'

The keychain doesn't exist yet (at the moment of this call) What can cause this exception?

回答1:

You need to use standard keys, so here your @"auth_token" is incorrect.

The keys that can be used for this purpose and the possible values for each key are listed in the “Keychain Services Constants” section.

source, with list of valid constants: Keychain Services Reference

For instance, you can use:

[_authenticationTokenKeychain setObject:authenticationToken forKey: (__bridge NSString *)kSecValueData];

回答2:

[_authenticationTokenKeychain setObject:authenticationToken forKey: @"auth_token"];  

For code snippet above, key param is only can use the keys provided from sdk. You can find all in SecItem.h