正确的方法来删除（清除）iOS应用程序的所有钥匙串数据

Question

I stored some information in the keychain, and there is a case that I need to remove all of the items, instead of doing [keychain removeObjectForKey:theKey] for all the keys, can I do:

NSDictionary *spec = [NSDictionary dictionaryWithObjectsAndKeys:(id)kSecClassGenericPassword, kSecClass,
                      [self serviceName], kSecAttrService, nil];

return !SecItemDelete((CFDictionaryRef)spec);

instead?

I tried it and it worked, just not sure if I am doing the correct thing?

Answer 1

在我的应用程序中，我正在使用此行来清除我的钥匙串：

[[[KeychainItemWrapper alloc] initWithIdentifier:@"my_key" accessGroup:nil] resetKeychainItem]

Answer 2

I believe what you are doing is correct, in fact, you can avoid the kSecAttrService parameter in your query if you want. On the other hand, the SecItemDelete returns a OSStatus value which you can check for more detailed information about the transaction.

    NSDictionary *spec = [NSDictionary dictionaryWithObjectsAndKeys:(id)kSecClassGenericPassword, kSecClass, nil];

    OSStatus status = SecItemDelete((CFDictionaryRef)spec);
    if (status == errSecSuccess)
       return YES;

    return NO;

Here are the codes and meanings for the possible status values