iOS8 Touch ID & Passcode - ios7

Question

i using this code in iOS 8 for security and uses touch ID
- (IBAction)authenticateButtonTapped{
LAContext *myContext = [[LAContext alloc] init];
NSError *authError = nil;
NSString *myLocalizedReasonString = #"Authenticate using your finger\r Scan Your Finger Now";
if ([myContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&authError]) {
[myContext evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics
localizedReason:myLocalizedReasonString
reply:^(BOOL succes, NSError *error) {
if (succes) {
[self showMessage:#"Authentication is successful" withTitle:#"Success"];
NSLog(#"User authenticated");
} else {
switch (error.code) {
case LAErrorAuthenticationFailed:
[self showMessage:#"Authentication is failed" withTitle:#"Error"];
NSLog(#"Authentication Failed");
break;
case LAErrorUserCancel:
[self showMessage:#"You clicked on Cancel" withTitle:#"Error"];
NSLog(#"User pressed Cancel button");
break;
case LAErrorUserFallback:
[self showMessage:#"You clicked on \"Enter Password\"" withTitle:#"Error"];
NSLog(#"User pressed \"Enter Password\"");
[self copyMatchingAsync];
break;
default:
[self showMessage:#"Touch ID is not configured" withTitle:#"Error"];
NSLog(#"Touch ID is not configured");
break;
}
NSLog(#"Authentication Fails");
}
}];
} else {
NSLog(#"Can not evaluate Touch ID");
[self showMessage:#"Can not evaluate TouchID" withTitle:#"Error"];
}
}
after for use the passcode system i copy this code from apple example
- (void)copyMatchingAsync
{
NSDictionary *query = #{
(__bridge id)kSecClass: (__bridge id)kSecClassGenericPassword,
(__bridge id)kSecAttrService: #"SampleService",
(__bridge id)kSecReturnData: #YES,
(__bridge id)kSecUseOperationPrompt: NSLocalizedString(#"AUTHENTICATE_TO_ACCESS_SERVICE_PASSWORD", nil)
};
dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
CFTypeRef dataTypeRef = NULL;
NSString *msg;
OSStatus status = SecItemCopyMatching((__bridge CFDictionaryRef)(query), &dataTypeRef);
if (status == errSecSuccess)
{
NSData *resultData = ( __bridge_transfer NSData *)dataTypeRef;
NSString * result = [[NSString alloc] initWithData:resultData encoding:NSUTF8StringEncoding];
msg = [NSString stringWithFormat:NSLocalizedString(#"RESULT", nil), result];
} else {
}
});
}
-(void) showMessage:(NSString*)message withTitle:(NSString *)title
{
UIAlertController * alert= [UIAlertController
alertControllerWithTitle:title
message:message
preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* cancel = [UIAlertAction
actionWithTitle:#"OK"
style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action)
{
[alert dismissViewControllerAnimated:YES completion:nil];
}];
[alert addAction:cancel];
[self presentViewController:alert animated:YES completion:nil];
}
its work great and rapid for fingerprint but the passcode system can't show and dosen't work. and i received "ERROR_ITEM_NOT_FOUND" = "error item not found";
this apple link https://developer.apple.com/library/ios/samplecode/KeychainTouchID/Introduction/Intro.html
but i can't good understand

Answer 1

Sorry to tell you but you can't do that.
You are mixing access control with keychain access, You don't have access to the user passcode.
using SecItemCopyMatching is possible if you added a resource with SecItemAdd using the same attributes (the contents of "query")

Answer 2

"ERROR_ITEM_NOT_FOUND" = "error item not found" show no item in keychain.
I also saw the Apple sample code "KeychainTouchID" as you said above.
iOS8's new feature make the developer can use the iPhone user's passcode & Touch ID for authentication.
You have to "Add Item" firstly, and then call "Query for Item".
If you want more convenient solution, maybe you can use SmileTouchID.
It is a library for integrate Touch ID & Passcode to iOS App conveniently that even support for iOS7 and the device that cannot support Touch ID.
You just need a few line of code and get what you want.
if ([SmileAuthenticator hasPassword]) {
[SmileAuthenticator sharedInstance].securityType = INPUT_TOUCHID;
[[SmileAuthenticator sharedInstance] presentAuthViewController];
}